Mentioned “zha_custom” fork by @le_top has been renamed to “zha-toolkit” and moved to a new repository from mdeweerd on GitHub and a Blueprint make it a bit easier to achieve nightly backups:
https://community.home-assistant.io/t/daily-znp-zigbee-coordinator-backup-blueprint/377149
https://github.com/mdeweerd/zha-toolkit
https://github.com/mdeweerd/zha-toolkit/blob/dev/README.md#znp_backup-backup-znp-network-data