If your Android TV has Chromecast built in then it is already an endpoint. Alternatively, a £35 Chromecast dongle plugged into a spare HDMI socket will make it an endpoint.
I’ve successfully side-loaded Roon Android versions to a Minix at the beginning of my Roon experience. it was fun tinkering and looked great on the TV screen. Everything worked fine, air mouse and all, except the fan noise! You should give it a try!