Hey In_Tor,
In reviewing your post, we see that you're having an issue with the microphone on your AirPods.
To clarify, you're unable to be heard if using your AirPods for a call? If so, can they not hear you at all, or does it sound distorted or just very low volume? What about other apps such as FaceTime?
Additionally, you've taken some great steps so far in isolating the issue. The next thing we'd recommend from here is to reset the AirPods.
If the issue persists, let us know the details requested and we will continue from there.
Cheers!