I'm not really sure why anyone would want to use an Apple TV for games, instead of a dedicated console. AFAICT the killer app for Apple TV is airplay. I haven't seen a co-working space conference room TV without an Apple TV attached for years.
I mean, I guess privacy is the other feature. I use an AppleTV at home to bypass all the smart TV nonsense. I know Apple can't be trusted, but I trust it more than a TV manufacturer who tries to shove ads down my throat the moment I connect their TV to the internet.
I refuse to use anything Apple so can't speak for the Apple TV, but I see it as pretty comparable to the Google TV (aka Chromecast w/ Google TV) products, just more open, flexible, compatible, and affordable.
I use Google TV for games on occasion. It has excellent controller support and works great for lightweight games that run fine on the stick. For anything heavier, the Steam Link app is the go-to. I can run the games on my bigass Linux PC and stream them to the TV. I routinely do this for Hogwart's Legacy for example.
Now that said, lately I've been just hooking up my Steam Deck to the TV and using that. Less friction and less bugs by avoiding the Steam Link app. And the Steam Deck is pretty close to a console (certainly much closer than it is to an Apple/Google TV), so perhaps I've just proven your point :-D