Is it possible to get Nextcloud to eat its own backups, and have it all actually be restore-able?
Synchronise an external storage directory from Nextcloud to your laptop, and download the Nextcloud database dump into that directory. Then, the only thing that needs to be backed up is the external storage. Oh, well, except for everything else…
Anyway, I think there's some kernel of an interesting backup flow here, in that my new Raspberry Pi NAS will have a place as a nightly restore-checking machine. Just have to figure out the details!