Head gestures to accept or decline calls does not work for me

To be fair, I don’t know that this is necessarily accessibility or VoiceOver related, but I figured I’d post here in case somebody else discovered that it is, in which case I can rule this out as a potential culprit.
First, my details:
iPhone SE, third generation
iOS 18.6
AirPods 4, noise canceling version

I understand that with my new AirPods, I’m supposed to be able to accept or decline calls using head gestures, such as nodding to accept the call or shaking my head to decline it. I have gone through the test in my AirPods settings and the gestures worked fine there, but they do not work when somebody actually calls me. I’ve insured that Siri is on, that announce calls and announce notifications is on, that focus mode is off, that my phone is not on silent and that in fact the head gestures feature is on in the AirPods settings, but still no luck. I’ve also tried restarting my phone, disconnecting and pairing my AirPods And even trying an older pair of AirPods 2, and the deeper issue might even be that I’m straight up not getting Siri call announcements, which I posted another thread about.
Another reason I’m starting a new topic about this is because the only one I found when searching the site seems to be related to beta testing. When I clicked on it, I could not pull up the forum thread, only a generic page about how to submit beta feedback.
If this topic has been covered, and even better, if it has been resolved, please feel free to direct me to the appropriate resource. Thank you!