Microsoft have confirmed to me that Windows 11 DOES NOT support the microphone on headsets with a mic via the 3.5mm jack plug. The mic is on headsets with mic is only supported via USB port.
Massive frustration after being told a load of rubbish on how to get the 3.5mm jack to work with mic.
Don't waste your time.... the mic wont work on the 3.5 jack.
Solution either buy USB headset (the mic will work then) or buy an adapter to convert your headset to USB (they are about £7 on Amazon)