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).
Self hosted nextcloud and any gallery app (e.g. default gallery app from grapheneos) works fine for me. The nextcloud app allows syncing of your fotos.