In your cloud sync app, you should be able to ask it to sync your camera folder - I know the nextcloud app asks if you want this, and you can also point it to specific folders to keep in sync.
If your self host cloud doesn’t have an app, just use https://play.google.com/store/apps/details?id=dk.tacit.android.foldersync.full to sync chosen folders.
https://www.collaboraoffice.com/nextcloud/ sounds like what you’re looking for. I’ve not tried it myself as I actually like the Google docs/sheets etc offering.