In addition to AirPod Pros, I've listened to the selected Spacial Audio tracks on my Apple TV 4k (newest). Which is connected to my 5.1 speaker system which supports Dolby Atmos.

I feel I more prominently hear spacial aspects with my home theatre than on my AirPod Pros. As you mentioned, the difference wildly depends on how the tracks are remixed, so there were some tracks that didn't have much difference.