When I was looking to replace my google tools, I couldn't find an easy to to alternative Google Photos. Things that were suggested like immich or Synology or ente required some level of technical know how or dedicated hardware. I ended up buying a Synology drive but I have issues with loading images/videos (it's extremely slow).
Ente is another option that I have been using for almost 2 years now. It's end-to-end encrypted and open source with an app on F-Droid. There have been a lot of updates over the last year that have significantly improved the experience using the app.