I've two of the newer style Apple TV: a 4K (aka 5th gen) and the older HD (aka 4th gen).
I had problems getting Audio Station to directly stream using Airplay 2 to these on the previous tvOS. It was semi-resolved by enabling PIN code access on the Apple TV's Airplay settings.
I've updated the 4K box to tvOS 13 and while it seems that Audio Station is streaming the music there is no sound coming out of the Apple TV. I once got the Apple TV displaying the album art and controls on the TV screen, yet no music. To test that the volume wasn't turned down somewhere I was able to Airplay from my iPhone to the Apple TV, also Audio Station could stream to my Denon AVR using DLNA (which is where the Apple TV is plugged in to). That worked.
Also, tested Audio Station to the Apple TV HD on tvOS 12 and that still works. So seems there may be a problem with tvOS 13, Airplay 2, and Audio Station.
I had problems getting Audio Station to directly stream using Airplay 2 to these on the previous tvOS. It was semi-resolved by enabling PIN code access on the Apple TV's Airplay settings.
I've updated the 4K box to tvOS 13 and while it seems that Audio Station is streaming the music there is no sound coming out of the Apple TV. I once got the Apple TV displaying the album art and controls on the TV screen, yet no music. To test that the volume wasn't turned down somewhere I was able to Airplay from my iPhone to the Apple TV, also Audio Station could stream to my Denon AVR using DLNA (which is where the Apple TV is plugged in to). That worked.
Also, tested Audio Station to the Apple TV HD on tvOS 12 and that still works. So seems there may be a problem with tvOS 13, Airplay 2, and Audio Station.