Photoprism’s app space is pretty bad, but there is an completely hacky yet reliable solution for Android:

1. PhotoBackup
2. The PhotoBackup server on your Photoprism server
3. A cron job that runs the photoprism import command every few minutes.

Since I’ve had this set up, it’s worked as well as Google Photos ever did for keeping my phone snaps synced to the server. It’s been more reliable than SyncThing for my data, reacting and syncing faster, and it doesn’t mysteriously periodically just stop running like SyncThing.

I don’t know if PhotoBackup is available for iOS, but if it is, it works a treat.