Hello, Gary0302,
Thanks for using Apple Support Communities, it's great to have you here.
Spatial Audio is a really cool feature and we want to help make sure it's working at its best for you. As you mentioned, spatial audio isn't available on all apps but Apple Music is definitely one that it should be working with. With that in mind, we want to recommend that you open up System Preferences > Accessibility and double check that "Play stereo audio as mono" isn't enabled here as this may interfere with spatial audio availability.
If that doesn't do the trick, see if you can reset your AirPods and reconnect them to your Mac. This may help refresh the connection and get this feature working as expected. If you have an iPhone available, here is how you can reset: How to reset your AirPods and AirPods Pro - Apple Support
We hope that this information is helpful.
Have a great day!