Earlier quoted context omitted.
> This. Why would you even connect TV to the network? I happen to have a NAS with family pictures I like to display. I can (and do) firewall that thing, but then you hit other issues like the apps you need to show pictures and movies in the first place not to install/run. I've yet to hear of a reasonable recipe to isolate and secure such connected TVs. And don't get me started on Chromecast or other Android dongles,…
Any SBC like Radxa Rock (cheap) to Orange Pi (powerful). 4k output, a linux you control, play retro games or stream torrent movies.
If you only care about file playback, bit still care about things like HDR and quality audio I would recommend something like the OSMC Vero V instead.
It's still relatively cheap, and open source, but also let's you playback something like a blu-ray rip without loss of quality.
It has the other bonus of not requiring any real setup or maintenance.