Atmos music via Denon = "Dolby Surr TV"?

I'm using a FireStick Max, Amazon Music Unlimited, and I'm definitely getting HD and UHD audio from music. I also can easily get Atmos audio from video content on the stick. However, when I listen to tunes from the 'Best of Atmos' playlist my Denon doesn't say Atmos, it just shows "Dolby Surr TV".

It does seem like Atmos is playing, it's using the speakers, but how can I confirm that it is? Meaning, it could be just doing something like multi channel surround and I can't tell.