Hey there,
I believe there might be a problem with the Hearing Test feature for developer beta user. I contacted a Genius and she believe that you might need to downgrade back to the public OS (for all OS). Here's the link to do that.
How to uninstall iOS or iPadOS beta software - Apple Support (CA)
You can also try resetting your AirPods Pro 2 but it didn't yield any results for me.
The Genius I talked to said that it's not available for Mac (it is), so if you come across anyone that says otherwise, be cautious about what they're telling you.
AirPods Pro 2 - Hearing Health Feature Availability - Apple (CA)
For anyone else that sees this, note: this feature is only available on the 2nd get AirPod Pros. You can check by looking for the speakers on the bottom of your case or the lanyard loop on the right side of your case.
I hope this helps!