I just run Debian with Kodi.
Helps to have something like this with a keyboard and air mouse/trackpad.
I either watch locally stored media or stuff on firefox though. Not sure about apps.
ETA: I see someone else here mentioned Plasma Bigscreen. If you choose Debian it won't be available for a while. It was removed from Debian 13 because it hadn't been updated in a while but someone has been working on it for a while now. Hopefully it'll be back soon.