I'm assuming you've deleted Google (and incidentally Google Photos) due to privacy concerns, or disliking the model of paywalling your precious memories. You can build a library for Photos.app on Mac, and store it on an external drive. I'm not sure what your backup method of choice is, but I'd recommend giving Immich a try, especially if you're into home servers. It's similar to Google Photos in function, is open source, respects your privacy, and is actively developed.