Take a TV, strap a mini PC like one of those BeeLink ones to the back (it comes with mounting hardware), plug an HDMI cable between them. Connect a wireless keyboard with trackpad, and congrats! You’ve got a big screen computer.
The next bits really depend on your technical know-how. What I did was wiped Windows from the PC and installed Linux, then installed Jellyfin and Firefox.
Jellyfin works as a media server so I can stream my own collection of videos/images anywhere im my home, and Firefox with uBlock Origin means I can log in to any streaming service I want, without the ads. And I can log into my (on-device) Jellyfin server the same way.
I’ve tried all the interfaces like XBMC/Kodi and Plesk etc. and find it’s more of a headache than just having a keyboard handy.