I apologize for my lack of knowledge. 
Raw LOG is (I hope) below.
logger setting:
default: critical
logs:
homeassistant.components.backup: debug
hassio.backup: debug
Backup from safe-mode has the same content as ‘regular’ one.
2026-10-05 13:06:08.511 DEBUG (MainThread) [homeassistant.components.backup] Unscheduling next automatic delete
2026-10-05 13:06:08.512 DEBUG (MainThread) [homeassistant.components.backup] Loading backup agents for hassio
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] Backup platform hassio loaded
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] 0 platforms loaded in total
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] 0 agents loaded in total
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] 0 local agents loaded in total
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] Backup platform recorder loaded
2026-10-05 13:06:08.513 DEBUG (MainThread) [homeassistant.components.backup] 1 platforms loaded in total
2026-10-05 13:06:08.514 DEBUG (MainThread) [homeassistant.components.backup] 0 agents loaded in total
2026-10-05 13:06:08.514 DEBUG (MainThread) [homeassistant.components.backup] 0 local agents loaded in total
2026-10-05 13:06:08.514 DEBUG (MainThread) [homeassistant.components.backup] Loaded 1 platforms
2026-10-05 13:06:08.514 DEBUG (MainThread) [homeassistant.components.backup] Loaded 0 agents
2026-10-05 13:06:12.212 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:06:16.193 DEBUG (MainThread) [homeassistant.components.backup] Backup platform ip_ban_manager loaded
2026-10-05 13:06:16.194 DEBUG (MainThread) [homeassistant.components.backup] 1 platforms loaded in total
2026-10-05 13:06:16.194 DEBUG (MainThread) [homeassistant.components.backup] 2 agents loaded in total
2026-10-05 13:06:16.194 DEBUG (MainThread) [homeassistant.components.backup] 0 local agents loaded in total
2026-10-05 13:06:16.194 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: BackupPlatformEvent(domain='ip_ban_manager')
2026-10-05 13:06:16.194 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] Loading backup agents for synology_dsm
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] Backup platform synology_dsm loaded
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] 1 platforms loaded in total
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] 3 agents loaded in total
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] 0 local agents loaded in total
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: BackupPlatformEvent(domain='synology_dsm')
2026-10-05 13:06:17.530 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:06:18.426 DEBUG (MainThread) [homeassistant.components.backup] Loading backup agents for backup
2026-10-05 13:06:18.426 DEBUG (MainThread) [homeassistant.components.backup] Backup platform backup loaded
2026-10-05 13:06:18.426 DEBUG (MainThread) [homeassistant.components.backup] 1 platforms loaded in total
2026-10-05 13:06:18.427 DEBUG (MainThread) [homeassistant.components.backup] 3 agents loaded in total
2026-10-05 13:06:18.427 DEBUG (MainThread) [homeassistant.components.backup] 0 local agents loaded in total
2026-10-05 13:06:18.427 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: BackupPlatformEvent(domain='backup')
2026-10-05 13:06:18.427 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:06:26.144 DEBUG (MainThread) [homeassistant.components.backup] Backup state: blocked -> idle
2026-10-05 13:06:26.144 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: IdleEvent(manager_state=<BackupManagerState.IDLE: 'idle'>)
2026-10-05 13:06:26.145 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:25:03.337 DEBUG (MainThread) [homeassistant.components.backup] Backup state: idle -> create_backup
2026-10-05 13:25:03.337 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=None, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:25:03.339 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:25:03.345 DEBUG (MainThread) [homeassistant.components.backup] Backup start notification
2026-10-05 13:25:03.345 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.HOME_ASSISTANT: 'home_assistant'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:25:03.345 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:25:03.352 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.HOME_ASSISTANT: 'home_assistant'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:25:03.353 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:13.800 DEBUG (MainThread) [homeassistant.components.backup] Backup end notification
2026-10-05 13:26:13.810 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.ADDONS: 'addons'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:26:13.810 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:33.666 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.FOLDERS: 'folders'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:26:33.666 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:38.431 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.FINISHING_FILE: 'finishing_file'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:26:38.432 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:38.436 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.FINISHING_FILE: 'finishing_file'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:26:38.436 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:38.446 DEBUG (MainThread) [homeassistant.components.backup] Generated new backup with backup_id fc0428f1, uploading to agents ['hassio.local', 'synology_dsm.2550V1R3MA9YT']
2026-10-05 13:26:38.446 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.UPLOAD_TO_AGENTS: 'upload_to_agents'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:26:38.446 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:26:38.446 DEBUG (MainThread) [homeassistant.components.backup] Uploading backup fc0428f1 to agents ['hassio.local', 'synology_dsm.2550V1R3MA9YT']
2026-10-05 13:26:38.447 DEBUG (MainThread) [homeassistant.components.backup] Uploading backup fc0428f1 to agent hassio.local as is
2026-10-05 13:26:38.447 DEBUG (MainThread) [homeassistant.components.backup] Uploading backup fc0428f1 to agent synology_dsm.2550V1R3MA9YT as is
2026-10-05 13:26:38.449 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: UploadBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, agent_id='hassio.local', uploaded_bytes=5737031680, total_bytes=5737031680)
2026-10-05 13:26:38.449 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:29:33.323 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: UploadBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, agent_id='synology_dsm.2550V1R3MA9YT', uploaded_bytes=5737031680, total_bytes=5737031680)
2026-10-05 13:29:33.323 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:29:33.324 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=<CreateBackupStage.CLEANING_UP: 'cleaning_up'>, state=<CreateBackupState.IN_PROGRESS: 'in_progress'>)
2026-10-05 13:29:33.324 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:29:34.019 DEBUG (MainThread) [homeassistant.components.backup] Backups returned by include filter: {'e6634a95': ManagerBackup(addons=[AddonInfo(name='Zigbee2MQTT', slug='45df7312_zigbee2mqtt', version='2.14.2-1'), AddonInfo(name='Advanced SSH & Web Terminal', slug='a0d7b954_ssh', version='24.1.7'), AddonInfo(name='Samba share', slug='core_samba', version='12.10.0'), AddonInfo(name='Scrutiny', slug='db21ed7f_scrutiny', version='v1.76.4'), AddonInfo(name='Samba Backup', slug='15d21743_samba_backup', version='5.2.0'), AddonInfo(name='Network UPS Tools', slug='a0d7b954_nut', version='0.18.1'), AddonInfo(name='Mosquitto broker', slug='core_mosquitto', version='7.1.1'), AddonInfo(name='File editor', slug='core_configurator', version='6.1.0'), AddonInfo(name='Glances', slug='a0d7b954_glances', version='0.23.1'), AddonInfo(name='SQLite Web', slug='a0d7b954_sqlite-web', version='6.1.1'), AddonInfo(name='TasmoBackup', slug='6a15710b_tasmobackup', version='1.08.00'), AddonInfo(name='TasmoAdmin', slug='a0d7b954_sonweb', version='0.34.0'), AddonInfo(name='Nginx Proxy Manager', slug='a0d7b954_nginxproxymanager', version='4.1.0'), AddonInfo(name='DbStats', slug='8bce8ef4_dbstats', version='0.5.12'), AddonInfo(name='ESPHome Device Builder', slug='5c53de3b_esphome', version='2026.9.1'), AddonInfo(name='Studio Code Server', slug='a0d7b954_vscode', version='7.2.0'), AddonInfo(name='chrony', slug='a0d7b954_chrony', version='6.1.0'), AddonInfo(name='SMS Gammu Gateway', slug='06c5e726_sms_gammu_gateway', version='1.7.1'), AddonInfo(name='SONOFF Dongle Flasher', slug='81bc2df9_sonoff_dongle_flasher_for_ihost', version='1.3.4'), AddonInfo(name='NetAlertX', slug='db21ed7f_netalertx', version='26.10.0'), AddonInfo(name='LMS Lyrion Music Server(Formerly Logitech Media Server)', slug='fc57b866_lms', version='9.1.1.0'), AddonInfo(name='Frigate (Full Access) Beta', slug='ccab4aaf_frigate-fa-beta', version='0.18.0'), AddonInfo(name='Piper', slug='core_piper', version='2.5.2')], backup_id='e6634a95', date='2026-10-05T08:11:06.412695+02:00', database_included=True, extra_metadata={'instance_id': '243ec2f4c2784b77bddfb9d12736dfb7', 'with_automatic_settings': True, 'supervisor.backup_request_date': '2026-10-05T08:11:06.412695+02:00'}, folders=[<Folder.SHARE: 'share'>, <Folder.SSL: 'ssl'>], homeassistant_included=True, homeassistant_version='2026.9.4', name='Automatic backup 2026.9.4', agents={'hassio.local': AgentBackupStatus(protected=False, size=5682749440), 'synology_dsm.2550V1R3MA9YT': AgentBackupStatus(protected=False, size=5682749440)}, failed_addons=[], failed_agent_ids=[], failed_folders=[], with_automatic_settings=True), '6f4db33a': ManagerBackup(addons=[AddonInfo(name='Zigbee2MQTT', slug='45df7312_zigbee2mqtt', version='2.14.2-1'), AddonInfo(name='Advanced SSH & Web Terminal', slug='a0d7b954_ssh', version='24.1.7'), AddonInfo(name='Samba share', slug='core_samba', version='12.10.0'), AddonInfo(name='Scrutiny', slug='db21ed7f_scrutiny', version='v1.76.4'), AddonInfo(name='Samba Backup', slug='15d21743_samba_backup', version='5.2.0'), AddonInfo(name='Network UPS Tools', slug='a0d7b954_nut', version='0.18.1'), AddonInfo(name='Mosquitto broker', slug='core_mosquitto', version='7.1.1'), AddonInfo(name='File editor', slug='core_configurator', version='6.1.0'), AddonInfo(name='Glances', slug='a0d7b954_glances', version='0.23.1'), AddonInfo(name='SQLite Web', slug='a0d7b954_sqlite-web', version='6.1.1'), AddonInfo(name='TasmoBackup', slug='6a15710b_tasmobackup', version='1.08.00'), AddonInfo(name='TasmoAdmin', slug='a0d7b954_sonweb', version='0.34.0'), AddonInfo(name='Nginx Proxy Manager', slug='a0d7b954_nginxproxymanager', version='4.1.0'), AddonInfo(name='DbStats', slug='8bce8ef4_dbstats', version='0.5.12'), AddonInfo(name='ESPHome Device Builder', slug='5c53de3b_esphome', version='2026.9.1'), AddonInfo(name='Studio Code Server', slug='a0d7b954_vscode', version='7.2.0'), AddonInfo(name='chrony', slug='a0d7b954_chrony', version='6.1.0'), AddonInfo(name='SMS Gammu Gateway', slug='06c5e726_sms_gammu_gateway', version='1.7.1'), AddonInfo(name='SONOFF Dongle Flasher', slug='81bc2df9_sonoff_dongle_flasher_for_ihost', version='1.3.4'), AddonInfo(name='NetAlertX', slug='db21ed7f_netalertx', version='26.10.0'), AddonInfo(name='LMS Lyrion Music Server(Formerly Logitech Media Server)', slug='fc57b866_lms', version='9.1.1.0'), AddonInfo(name='Frigate (Full Access) Beta', slug='ccab4aaf_frigate-fa-beta', version='0.18.0'), AddonInfo(name='Piper', slug='core_piper', version='2.5.2')], backup_id='6f4db33a', date='2026-10-05T10:11:22.484982+02:00', database_included=True, extra_metadata={'instance_id': '243ec2f4c2784b77bddfb9d12736dfb7', 'with_automatic_settings': True, 'supervisor.backup_request_date': '2026-10-05T10:11:22.484982+02:00'}, folders=[<Folder.SSL: 'ssl'>, <Folder.SHARE: 'share'>], homeassistant_included=True, homeassistant_version='2026.9.4', name='Automatic backup 2026.9.4', agents={'hassio.local': AgentBackupStatus(protected=False, size=5702369280), 'synology_dsm.2550V1R3MA9YT': AgentBackupStatus(protected=False, size=5702369280)}, failed_addons=[], failed_agent_ids=[], failed_folders=[], with_automatic_settings=True), 'fc0428f1': ManagerBackup(addons=[AddonInfo(name='Zigbee2MQTT', slug='45df7312_zigbee2mqtt', version='2.14.2-1'), AddonInfo(name='Advanced SSH & Web Terminal', slug='a0d7b954_ssh', version='24.1.7'), AddonInfo(name='Samba share', slug='core_samba', version='12.10.0'), AddonInfo(name='Scrutiny', slug='db21ed7f_scrutiny', version='v1.76.4'), AddonInfo(name='Samba Backup', slug='15d21743_samba_backup', version='5.2.0'), AddonInfo(name='Network UPS Tools', slug='a0d7b954_nut', version='0.18.1'), AddonInfo(name='Mosquitto broker', slug='core_mosquitto', version='7.1.1'), AddonInfo(name='File editor', slug='core_configurator', version='6.1.0'), AddonInfo(name='Glances', slug='a0d7b954_glances', version='0.23.1'), AddonInfo(name='SQLite Web', slug='a0d7b954_sqlite-web', version='6.1.1'), AddonInfo(name='TasmoBackup', slug='6a15710b_tasmobackup', version='1.08.00'), AddonInfo(name='TasmoAdmin', slug='a0d7b954_sonweb', version='0.34.0'), AddonInfo(name='Nginx Proxy Manager', slug='a0d7b954_nginxproxymanager', version='4.1.0'), AddonInfo(name='DbStats', slug='8bce8ef4_dbstats', version='0.5.12'), AddonInfo(name='ESPHome Device Builder', slug='5c53de3b_esphome', version='2026.9.1'), AddonInfo(name='Studio Code Server', slug='a0d7b954_vscode', version='7.2.0'), AddonInfo(name='chrony', slug='a0d7b954_chrony', version='6.1.0'), AddonInfo(name='SMS Gammu Gateway', slug='06c5e726_sms_gammu_gateway', version='1.7.1'), AddonInfo(name='SONOFF Dongle Flasher', slug='81bc2df9_sonoff_dongle_flasher_for_ihost', version='1.3.4'), AddonInfo(name='NetAlertX', slug='db21ed7f_netalertx', version='26.10.0'), AddonInfo(name='LMS Lyrion Music Server(Formerly Logitech Media Server)', slug='fc57b866_lms', version='9.1.1.0'), AddonInfo(name='Frigate (Full Access) Beta', slug='ccab4aaf_frigate-fa-beta', version='0.18.0'), AddonInfo(name='Piper', slug='core_piper', version='2.5.2')], backup_id='fc0428f1', date='2026-10-05T13:25:03.340733+02:00', database_included=True, extra_metadata={'instance_id': '243ec2f4c2784b77bddfb9d12736dfb7', 'with_automatic_settings': True, 'supervisor.backup_request_date': '2026-10-05T13:25:03.340733+02:00'}, folders=[<Folder.SSL: 'ssl'>, <Folder.SHARE: 'share'>], homeassistant_included=True, homeassistant_version='2026.9.4', name='Automatic backup 2026.9.4', agents={'hassio.local': AgentBackupStatus(protected=False, size=5737031680), 'synology_dsm.2550V1R3MA9YT': AgentBackupStatus(protected=False, size=5737031680)}, failed_addons=[], failed_agent_ids=[], failed_folders=[], with_automatic_settings=True)}
2026-10-05 13:29:34.020 DEBUG (MainThread) [homeassistant.components.backup] Backups returned by include filter by agent: {'hassio.local': ['e6634a95', '6f4db33a', 'fc0428f1'], 'synology_dsm.2550V1R3MA9YT': ['e6634a95', '6f4db33a', 'fc0428f1']}
2026-10-05 13:29:34.020 DEBUG (MainThread) [homeassistant.components.backup] Backups returned by delete filter: {}
2026-10-05 13:29:34.020 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: CreateBackupEvent(manager_state=<BackupManagerState.CREATE_BACKUP: 'create_backup'>, reason=None, stage=None, state=<CreateBackupState.COMPLETED: 'completed'>)
2026-10-05 13:29:34.020 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)
2026-10-05 13:29:34.021 DEBUG (MainThread) [homeassistant.components.backup] Backup state: create_backup -> idle
2026-10-05 13:29:34.021 DEBUG (MainThread) [homeassistant.components.backup] Received backup event: IdleEvent(manager_state=<BackupManagerState.IDLE: 'idle'>)
2026-10-05 13:29:34.023 DEBUG (MainThread) [homeassistant.components.backup] Finished fetching backup data in 0.000 seconds (success: True)