I use to use Plex, but they changed the UI to include all sorts of junk that I didn't want; really made it unusable for me as I didn't want adult films (not porn, but not kids friendly) being advertised on the home screen. I only used it for pictures and home videos but they wrecked it; couldn't find a way to go back.

I unfortunately bought a roku right before all this went down, but fortunately there's a Jellyfin app for it. Jellyfin is an open source media server that is probably the closest to Plex in functionality.

The home screen and side bars are all fully customizable. It's a little annoying they turn them on by default as they add channels but you can turn them off easily.

I tried turning everything off, still had content thumbnails and details I didn't want and lacked the home screen stuff I did (it has been great previously). Waited for the next two revisions to see if it was fixed, no better so I moved on. Sounds like it's good for you: I literally wanted only local network content, nothing from the net, is that how you have it?

Might consider going back but we don't look at family pics that often and vlc works well enough.