Man I just got a mini-itx case and use a full-blown windows desktop next to my TV. Bought a "fly-mouse" (wireless mouse that works with gyroscope), set screen DPI to 200%.

One thing I didn't expect is that my family ends up using the TV quite a lot for planning stuff, like doing google sheets, planning trips on google maps, booking planes/restaurants/concerts/etc. We have a small normal wireless mouse and keyboard for such occasions.

No regrets, open platform > closed junk. Can also play steam games on TV. Can't wait until Steam OS works well on desktop so I can ditch windows too. If you only care about media and not gaming you can get a case small enough that can fit hidden away in a cabinet.