I used PhotoPrism some time ago when it was slightly less featured, but wasn't satisfied with it. The dealbreaker for me is auto mobile backup. PhotoPrism relies on a third party app to "sync" photos, which isn't the same as backing them up. With that said, PhotoPrism is all the rage in the self-hosting community and I can definitely see why.

Conversely, Synology Photos (which I use instead now) has a fantastic mobile app. However, if you really want reliable and granular object/face recognition, the Syno app is a little bare bones. It does some face recog but that's really it. However, its backup feature is reliable and I don't have to worry about if it's working in the background or not. I tried Nextcloud's photo plugin for a while too, but its mobile app had issues and I just couldn't rely on it.

Another project I've been keeping my eye on is immich: https://github.com/immich-app/immich

I'm happy for now with Syno Photos but it would be nice to have my photo app in my container environment with everything else I run and just use the NAS for media storage like I intended to.