The main menu/home page does not serve ads. It just lists your installed apps.
Using the Apple TV app (which aggregates listings from most services, Netflix being the notable exception) will list shows on services you might not already pay for. But, you don’t have to use the Apple TV app - you can just go straight to the apps you know you want.
Using the Apple TV app (which aggregates listings from most services, Netflix being the notable exception) will list shows on services you might not already pay for. But, you don’t have to use the Apple TV app - you can just go straight to the apps you know you want.