I have tried 2 different bluetooth headsets with the same result. The headsets are Airpods v2 and NERO-TX.
I am running kernel 6.4.15-200.fc38.x86_64 on a Dell Inc. XPS 9320.
When I select Headphone, it swithces Input to built-in microphone. If I select Handsfree in Input now, it swithces Output to Handsfree (where sound is not working).
The problem is the output volume, not the input volume. The output (bluetooth headset) just plays noise, when Handsfree (and not Headphone) is selected.
If I wan’t to use the microphone, the sound output is forced to Handsfree (where sound is not working).
Understood, but if you have an active mic with the input volume maxed out (as it appears you have) then it will have both input and output active. Thus unwanted noise, possibly even feedback.
It would at least be worth a try at reducing the input volume to see if that has any affect.