I'm pretty happy with Synology Photos on my NAS. It's got face detection, interprets the exif and gives you geo maps, has albums and sharing. Got it set up for my entire family.

It doesn’t back up photos. It exports them. Not the same. Take a slow motion video. The version on your NAS will be 30 FPS, slowed down in the middle. For a backup I expect it to be the 240 FPS version.

Does it have mobile upload?

Sure!