With the Apple TV 4K if you don't have an Atmos receiver but it is 7.1,an extractor is the way to go. You will get 5.1 from Apple Music and 7.1 from apps such as Netflix. It all depends on the core of the Atmos. But you need the extractor between the Apple box and your receiver. But without an Atmos receiver 5.1 is the best that you are going to get from Apple Music unless they change the core in their music to 7.1. With the extractor, with Apple music, you are going to see 7.1 on your receiver but the back speakers will have nothing in them. From when I was using Tidal, their Atmos didn't even seem to have a core or had a stereo core so stereo was the best.