@Garacesh
I was having this exact same issue with my WH62 on Windows 11. I found several items across the Interverse but nothing seemed to fix it. I wanted to come out here and provide what fixed it for me in case anyone else comes across this post and is pulling their hair out.
My problem was related to the Microsoft Teams Setting under devices to automatically adjust mic sensitivity. I basically just had to turn that value off and that allowed me to adjust the Microphone Input Volume slider.
Once I did that step, I was able to turn that setting back on and it continued to work as expected. Now I don't recall if that was the exact steps. There may have been some form of turn that setting off, then plug in the headset, adjust the slider, then turn it back on but I know turning that setting off adjusting the slider allowed my microphone to start working again.
I know it has been sever months since you posted this and perhaps you found the solution already but if not, I hope this works.