I wish there was a reasonably cheap, sufficiently powerful TV box compatible with a free distribution Android TV. Something like Graphene/Lineage for TVs. Lineage does in fact have some TV builds, but there is basically no suitable new hardware for it AFAIK.

At the moment the best option still seems to be a somewhat old mini-PC with Linux and Plasma Bigscreen. But you need to add an HDMI-CEC dongle, and airmouse remote, and Waydroid if you want a more typical TV box experience.

> But you need to add an HDMI-CEC dongle

Little tip, but at least with my AMD card and the right DP->HDMI cable you can get CEC tunneled over Display Port without the dongle.

Your best bet is indeed a mini PC. I think you can probably still find N100 based mini PCs pretty cheap. As for keyboard, you can find a micro 6" keyboard + touchpad (ie K808) for like $25 on Amazon.