I’m having same exact delayed startup. I spotted icloud3 custom component in your log. I too am running the same custom_component and have been troubleshooting it with @gcobb321 for a bit. Try commenting out the icloud3 device tracker from config.yaml and restart and see if it starts fast/normal.
Notice in the snip below the last 3 log lines and the timestamps. After the device_tracker 300 second timeout, bootstrap waits another 300 seconds before timing out. Total startup time - 605 seconds.
I have a hunch this startup delay/timeouts are causing issues/race conditions with the icloud3 component startup logic.
I’ve reproduced this on a clean VM running the 2021.9.x but also have seen the problem on 2021.8.x. I don’t have anything else running on the environment.
2021-09-07 11:49:55 INFO (MainThread) [homeassistant.bootstrap] Setting up stage 1: {'cloud', 'person', 'onboarding', 'system_log', 'device_automation', 'websocket_api', 'http', 'lovelace', 'search', 'analytics', 'image', 'api', 'webhook', 'auth', 'hassio', 'config', 'frontend'}
2021-09-07 11:49:55 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'cloud': <cloud: 0 / 1>, 'person': <person: 0 / 1>, 'onboarding': <onboarding: 0 / 1>, 'lovelace': <lovelace: 1 / 0>, 'analytics': <analytics: 0 / 1>, 'hassio': <hassio: 1 / 0>, 'frontend': <frontend: 0 / 1>, 'image': <image: 1 / 0>}
2021-09-07 11:49:55 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'lovelace': 0.662267, 'hassio': 0.631032, 'config': 0.620144, 'search': 0.39171, 'image': 0.001515}
2021-09-07 11:49:56 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'onboarding': <onboarding: 0 / 1>, 'hassio': <hassio: 1 / 0>, 'frontend': <frontend: 0 / 1>, 'person': <person: 2 / 0>, 'cloud': <cloud: 1 / 0>}
2021-09-07 11:49:56 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'hassio': 1.684718, 'person': 0.875192, 'cloud': 0.002089}
2021-09-07 11:49:57 INFO (MainThread) [homeassistant.bootstrap] Setting up stage 2: {'tts', 'tag', 'script', 'input_select', 'wled', 'updater', 'trace', 'device_tracker', 'group', 'map', 'usb', 'blueprint', 'scene', 'network', 'zeroconf', 'input_number', 'media_source', 'counter', 'timer', 'system_health', 'input_boolean', 'mobile_app', 'automation', 'dhcp', 'input_datetime', 'zone', 'history', 'logbook', 'sun', 'ssdp', 'esphome', 'input_text', 'energy', 'my', 'default_config'}
2021-09-07 11:49:58 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'tts': <tts: 0 / 1>, 'tag': <tag: 1 / 0>, 'script': <script: 0 / 1>, 'input_select': <input_select: 1 / 0>, 'wled': <wled: 0 / 1>, 'device_tracker': <device_tracker: 0 / 1>, 'group': <group: 1 / 0>, 'usb': <usb: 0 / 1>, 'scene': <scene: 2 / 0>, 'network': <network: 0 / 1>, 'zeroconf': <zeroconf: 0 / 1>, 'input_number': <input_number: 1 / 0>, 'media_source': <media_source: 1 / 0>, 'counter': <counter: 1 / 0>, 'timer': <timer: 1 / 0>, 'system_health': <system_health: 1 / 0>, 'input_boolean': <input_boolean: 1 / 0>, 'mobile_app': <mobile_app: 0 / 1>, 'automation': <automation: 0 / 1>, 'input_datetime': <input_datetime: 1 / 0>, 'zone': <zone: 1 / 0>, 'logbook': <logbook: 1 / 0>, 'ssdp': <ssdp: 0 / 1>, 'esphome': <esphome: 0 / 1>, 'input_text': <input_text: 1 / 0>, 'energy': <energy: 0 / 1>, 'default_config': <default_config: 0 / 1>}
2021-09-07 11:49:58 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'tag': 1.637401, 'input_select': 1.636359, 'group': 1.615744, 'scene': 1.603616, 'scene.homeassistant': 1.603149, 'input_number': 1.602269, 'media_source': 1.559125, 'counter': 1.546184, 'timer': 1.545182, 'system_health': 1.544257, 'input_boolean': 1.543468, 'input_datetime': 0.162763, 'zone': 0.162186, 'logbook': 0.133005, 'input_text': 0.072012, 'sensor': 0.009625, 'binary_sensor': 0.007233}
2021-09-07 11:49:59 DEBUG (MainThread) [homeassistant.components.websocket_api.http.connection] [139778701429872] Received {'type': 'subscribe_bootstrap_integrations', 'id': 58}
2021-09-07 11:49:59 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>, 'sensor': <sensor: 1 / 0>, 'default_config': <default_config: 1 / 0>}
2021-09-07 11:49:59 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'wled': 0.971901, 'device_tracker': 0.751532, 'device_tracker.icloud3': 0.659372, 'sensor.mobile_app': 0.606237, 'default_config': 0.016992}
2021-09-07 11:50:00 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>}
2021-09-07 11:50:00 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'device_tracker': 1.75267, 'device_tracker.icloud3': 1.66051}
2021-09-07 11:50:01 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>}
2021-09-07 11:50:01 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'device_tracker': 2.755229, 'device_tracker.icloud3': 2.663069}
2021-09-07 11:50:03 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>}
2021-09-07 11:50:03 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'device_tracker': 3.781756, 'device_tracker.icloud3': 3.689596}
2021-09-07 11:54:57 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>}
Above repeats for 300 seconds...
2021-09-07 11:54:57 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'device_tracker': 298.720789, 'device_tracker.icloud3': 298.628629}
2021-09-07 11:54:58 DEBUG (MainThread) [homeassistant.bootstrap] Running timeout Zones: {'device_tracker': <device_tracker: 1 / 0>}
2021-09-07 11:54:58 DEBUG (MainThread) [homeassistant.bootstrap] Integration remaining: {'device_tracker': 299.721338, 'device_tracker.icloud3': 299.629178}
2021-09-07 11:54:59 DEBUG (MainThread) [homeassistant.bootstrap] Integration setup times: {'select': 0.001268, 'system_log': 0.001302, 'logger': 0.001397, 'stream': 0.004593, 'switch': 0.005894, 'notify': 0.010692, 'onboarding': 0.011393, 'usb': 0.01556, 'light': 0.024841, 'auth': 0.02712, 'webhook': 0.033371, 'cloud': 0.034243, 'api': 0.036845, 'automation': 0.037544, 'my': 0.039448, 'default_config': 0.054385, 'websocket_api': 0.063617, 'device_automation': 0.063843, 'frontend': 0.083648, 'image': 0.092947, 'script': 0.096987, 'analytics': 0.104347, 'ssdp': 0.105621, 'sun': 0.113886, 'history': 0.128164, 'binary_sensor': 0.128416, 'sensor': 0.130485, 'network': 0.142807, 'dhcp': 0.155552, 'zeroconf': 0.157783, 'energy': 0.25472, 'logbook': 0.297836, 'tts': 0.359669, 'input_text': 0.363913, 'search': 0.391904, 'esphome': 0.411711, 'http': 0.41928, 'recorder': 0.420148, 'input_datetime': 0.4545, 'zone': 0.472206, 'config': 0.697782, 'lovelace': 0.753953, 'person': 0.8895, 'mobile_app': 1.083791, 'wled': 1.226784, 'blueprint': 1.561571, 'map': 1.563358, 'trace': 1.565831, 'system_health': 1.708943, 'media_source': 1.723665, 'homeassistant': 1.751842, 'updater': 1.765326, 'scene': 1.767917, 'group': 1.779136, 'tag': 1.803146, 'input_boolean': 1.834971, 'timer': 1.836601, 'counter': 1.837506, 'input_number': 1.893463, 'input_select': 1.897238, 'hassio': 2.15011, 'device_tracker': 300.002439}
2021-09-07 11:54:59 DEBUG (MainThread) [homeassistant.bootstrap] Waiting for startup to wrap up
2021-09-07 11:59:59 WARNING (MainThread) [homeassistant.bootstrap] Setup timed out for bootstrap - moving forward
2021-09-07 11:59:59 INFO (MainThread) [homeassistant.bootstrap] Home Assistant initialized in 605.00s