Used ADB to remove all Google apps and system apps from the Android TV box given by my ISP including Google Play Services. It works fine, though removing Play Services could be be problematic for other android TV boxes.
I'm using Aurora Store (works fine with a remote) and an F-Droid client for Android TV to manage app updates. Aptoide TV is also an option.
Edit: I use NewPipe and SmartTube instead of the YouTube app, and they don't need Google Play services. And also, setting up adblocking and tracker blocking DNS like AdGuard DNS blocks any ads and trackers from any apps running on the TV.
Source: r/degoogle · by /u/_TheFifthDimension