Lots of people have mentioned rsynx, restic, borgbackup, and others, but which would be best for backing up nextcloud, immich, and radicale? Do all of them have a method of automatically backing up every X days/weeks? Why use one over the other, what are the differences?
This is why I switched everything to single disk ZFS. The ability to snapshot everything with zero downtime, including data in case I ever misconfig something, as well as replicate all of it to other ZFS drives offsite in the most efficient way possible — including encrypted data without transferring the keys — was a no brainier.
It isn’t a full backup strategy, but it has features that no other backup software can do anywhere near as easily or efficiently.