@joyager one of the comments mentions it has a gallery app that does tagging, location tagging and sharing: https://social.privacytools.io/@kravietz/105196155802768059
I suspect that would be https://github.com/nextcloud/photos/ which looks promising.

As indicated in my follo-up post in the thread, I am still looking for an alternative to #gPhotos myself and am welcoming suggestions.

The entire thread already has some interesting suggestions, such as #digikam, #OwnPhotos, the aforementioned #NextCloudPhotos, #Plex and #SynologyMoments.