AppleTV Sound:Change format On disables Atmos

I searched for about 90 minutes, and I've found some old threads (3 plus years old), but nothing recent shows up:

I've got the newest AppleTV 4K, a Sony XBR75Z8H TV, and a McIntosh MHT300. When I set the Audio: Change Format to ON, the new format allows Stereo and Dolby Digital 5.1, but immersive audio greys out and is not available BUT The receiver says Dolby Digital. When playing an Atmos movie, I get Dolby Digital but not Atmos.

On the other hand, if I set the Audio: Change Format to OFF, Immersive Audio works, and I can check Dolby Atmos to ON. Now, if I have an Atmos signal, the receiver shows Atmos, but if I'm watching a non-Atmos source, the receiver reads PCM.

I'd love to to be able to watch Dolby Digital movies in Dolby Digital and Atmos movies in Atmos without having to go to the audio menu and switch to not change formats. Not only does it change the 'words' on the receiver, but it sounds different.

Thanks!

Bob