An Apple TV 4K paired with a receiver should be great, but it isn’t
Receivers are worth the price of admission if you’re looking for the best audio you can get. What makes them worth it is their ability to handle all the incoming audio without relying on a third-party source. This means that if your TV doesn’t support Dolby Atmos, it’s not a big deal because the receiver can do it for you. You can plug in all your devices to the receiver and not have to worry about your audio ever again. At least, that’s the way it should work.