Apple Music Dolby Atmos releases are actually two sets of recordings.  There is a Dolby Atmos stream and a stereo stream depending on your device capabilities/settings.

I propose we handle this the way we handle SACD's which present themselves as stereo or multichannel depending on players settings/capabilities.

So we should have medium formats for this case

Digital Media (Dolby Atmos stream)

Digital Media (stereo stream)

Apple music releases with Dolby Atmos versions would have two mediums, one to represent the Dolby Atmos tracks/recordings and one to represent the stereo tracks/recordings.

A complication to consider is that often only one track on a release is in Dolby Atmos, or the main album is in Dolby Atmos but the bonus tracks are not so you could have cases where the Dolby Atmos stream only has "track 5" and the stereo stream has all the tracks, etc.  Maybe need a style guideline on how to handle that.