M4 Mac mini plugged into an Atmos receiver. Only stereo output

Trying to play Dolby Atmos music from my Apple Music account but only getting a stereo output.

I connected my M4 Mac mini directly to my Devon AVC-X3700H (HDMI 5 - Game input).

I'm using the M4 Mac mini. HDMI passthrough enabled. Also switched to 8 ch on audio MIDI setup, and sat it to 5.1.2. That itself actually has a weird issue in configure speakers where the height speakers is coming from the rear ones instead. Don't know what to do about that.

I've enabled Dolby Atmos in Music Settings and still only getting Stereo.

I have also tried using the Plex app on my mini. This also only plays in stereo. The has on the front of it "Multi In Apple".