So local playback implies something more like a mini-ITX PC or SBC running some flavor of Linux. That’s fine, but it’s not going to be terribly couch-friendly since it’s going to have a bog standard desktop UI.
So the most popular option is to put all your media on a server in the closet (usually an old laptop or raspi or something), with a client on your streaming box like Plex, Kodi, Infuse, etc connecting to your server.
Never heard of Infuse but don't Plex and Kodi both contact the vendor's server? That is enough to make me not want to go anywhere near them. I do know there are home media center distros for the RPI and PC and they are supposedly nice. I'd be ok with using one in principle, but I haven't cared that much about media UI to bother. I just use command line mplayer on my laptop if I want to watch a video, and that's good enough for me. I can understand other people wanting a more TV-like experience, which is also fine.
* Plex tracks what you've watched so you don't have to remember what episode you left off on
* Plex serves up rich metadata when browsing your library
The Apple TV is a drop-in replacement for a Roku or Fire TV that lacks built-in advertising
