Music on Mac is pretty buggy.Hmm, weirdly Dolby Atmos seems to turn off randomly (between songs) for me, even with all settings enabled. I play one song with it enabled, and then the next song it's off for some reason. And I'm talking about playing music from Apple's own Made for Spatial Audio playlist. When I quit the Music app and restart and try the exact same song again, it works again... weird.
(Using 2021 iMac with macOS 11.4)