Now, just to throw it out there, my actual ‘critical data’ is way smaller than my total backed up data

That’s also the case for me. I’d probably count a few GB as critical. Contacts, Calendar, some photos, some documents.

If nextcloud (or some other alternative) has the ability to regularly export these things to an on-disk location, I could definitely backup that to some cheap hetzner server. This will not be a pbs backup, but I can get by with an offsite-backup done by something like restic or rsnapshot

Thank you for your advice!