I'd probably just buy a Synology station. Yes it's proprietary but the system itself is really good. I know a lot of people buy one just for its own photos system alone https://www.synology.com/en-global/dsm/feature/photos
You should look around on /r/homelab there are some nice low power consumption builds there, for example this one
https://www.reddit.com/r/homelab/comments/1935nar/homelab_na...