Immich as recommended by a few others, and there’s also Nextcloud, but keep in mind Nextcloud is a little “heavier” in that it has more functions and features. For example it can be used as a drive, calendar, contacts, and photo alternative. Look into a addin for Nextcloud called memories that I personally like better than the native photo app. I run both immich and Nextcloud, as well as a bunch of other alternatives to Google’s services.