I have years worth of photos backed up from my phone (android) on Nextcloud, it’s working pretty well… but it matters how you set up the auto upload and a few other things, and I’mnot claiming it’s without issues.
For example, I set it to move files into Nextcloud’s folder after uploading, so they appear as locally synced, and can be deleted to free up space if needed (maybe even automatically, not sure). Also, I set it to also upload existing files, because since they get moved, anything that’s still there clearly needs to be uploaded.
There are a few issues viewing media from the app, sometimes, but I use the Memories app :)
I’ve been meaning to try immich, looks pretty good, but I use Nextcloud for much more than just photos, so I’d have to keep both and have them sync somehow, and I’m not sure how to do that.
I get a bunch of upload errors for photos that I delete or move before nextcloud has a chance to upload them, those are safe to ignore. Not sure which errors you’re getting…
Forget about the plain nextcloud photos app, use the Memories app (incl. the android app).
Not as good as immich, from what I understand, but if you already have nextcloud, or need more than just photos, it works well.
It’s definitely not perfect, but since I was able to set it up to work well for me, I’m keeping it, at least until I have time to install immich and figure out how to sync the two (and maybe get a more powerful server to use its ML features). I’m currently running it off of a decade old chromebox …