Dolby Atmos/Spatial Audio "Automatic" Setting Incorrectly Assumes Compatibility

I've had this issue for a while and have not been able to find any kind of conclusive answer anywhere.

Running an iPhone 15 Pro on iOS18.5.

I prefer for my AirPods Pro to utilize Dolby Atmos for Apple Music when available. Initially I wasn't a fan of those mixes, but the personalized Spatial Audio feature made a night and day difference for me.

The problem is that when I have the setting for Dolby Atmos marked as "automatic", it incorrectly assumes that the aux cord in my car (an official Apple USB-C to 3.5mm) is a Dolby Atmos capable connection. It sounds markedly worse than the stereo output for this use, and based on the "automatic" setting, it should only be outputting the Atmos/spatial mix to supported Apple or Beats headphones.

If there was a toggle right there on the Apple Music app this wouldn't be much of an annoyance to turn it off as needed, but as it stands you have to go four menu pages deep in settings to access it. Has anyone else had this issue or found some kind of solution? I've tried the "forget all usb accessories" to make sure it was not recognizing that aux cord as headphones and the problem persists.

TL/DR, Dolby Atmos "automatic" setting recognizes non-Apple/Beats outputs as DA compatible.