Apple TVs can’t be turned off, AFAIK. The remote can put the Apple TV to sleep, or they will go to sleep automatically after a period of inactivity (which is configurable from the settings menu).
Having said that, there’s been some recent activity re: Hubitat and the SofaBaton X1S here.
My SofaBaton X1S can control my Apple TV 4K (the most recent generation) just fine, but I haven’t bothered to try putting the Apple TV to sleep with it (just the TV and AV receiver we use to watch Apple TV), since the Apple TV will go to sleep on its own anyway.
