Google isnt one to avoid puzzling branding changes, and the entire Google TV/Android TV thing is just the most recent in a long line of examples. The new Google TV interface will pertain to third-party devices eventually, however the OS will still be called Android TV, at least for a little while. Now, the new Chromecast with Google TV is the only device to officially support the updated UI, but there is a way to get it working on other Android Television hardware.
How-To Geek has a terrific explainer on this, but you need to be prepared to fiddle with designer settings and ADB commands if you desire to get it running. Your ATV device will need to be on Android 9 Pie or greater for this to work. The Google TV user interface is consisted of two parts, the Google TV Home launcher and a separate app that handles the search function. How-To Geek has downloads for both of these, with the previous coming from our sister site APK Mirror.
Head over to How-To Geek for exactly which commands you require to use, however it shouldnt take too much time to get Google Television up and running. The secret is uninstalling the default Android TV launcher so it doesnt interfere with the new one.
The home button on your Android TV gadgets remote will now take you to the new homescreen and the search tab must also work as anticipated. Be warned, this isnt rather the complete Google TV experience– it does not have the new settings menu and performance might not be as smooth as it must be. Its not bad as a substitute up until your device gets the complete update, however, and its definitely an upgrade over previous attempts to get this dealing with older hardware.