DEVONthink has no built in file backup capabilities. A proper backup strategy is up to the individual to implement and maintain. Due to the simplicity of Apple’s Time Machine, we suggest using it with local external drives. For an online backup, you can use a cloud backup service that uses a snapshot-style backup, ie. not “continuous backups”. Arq is one such service.

Unfortunately, there are no granular and accessible backups in iOS or iPadOS. The backup to iCloud is meant only for setting up or restoring a complete mobile device.

At this time, while sync is not intended as a backup, it may be used as a current backup of a database. Since the data is only useful to DEVONthink and DEVONthink To Go, it is not a true, product-independent backup, though.

Alternatively, you can export databases a files-in-folders to the Files app and back them up from there.

While sync can be used to restore a database in an emergency, sync should not be your only backup. The sync data is chunked, DEVONthink-specific raw data about the databases and is only useful to DEVONthink or DEVONthink To Go. A proper backup should be application-agnostic.