Putting my hat in this ring, too. I do a write-only sync of pictures from my phone to my NAS (upload new files and leave them on the phone - I prefer one way sync), and a mailbox-style sync of Signal backups (Signal can be configured to drop a backup file into a specified folder; I've configured FolderSync to upload whatever it finds there weekly and delete the backup locally). Finally, I do a two-way sync of my personal notes text file.

I don't have a good situation figured out for browsing unsorted uploaded photos, and I find that this is fine for my usage. I put a curated set of personal albums on a password protected personal site for friends and family. I enjoy the role of family chronicler.

My NAS is backed up via daily snapshot to a remote location.

YMMV!