@raksrules extract this zip in a folder (it's double zipped so that I could post it here). I have made 4 variations. Try them in ascending order.
Just double click on exe starting with 1. If it doesn't work then move on 2 so on and so forth. Everytime you open one of the exe, it'll add an icon 'H' in the system tray. Don't forget to quite that before trying different exe.
Also make sure your mic is your default recording device because it only mutes default recording device.
.ahk files contain source code of the respective exes. You don't need admin privileges unless you want to modify the source code yourself. Windows may give you threat warning which is normal as windows hasn't seen these exes before. Ignore that.
Talking about 4 variations,
1_mic-mute-traditional-volume : play pause media button toggles mic
2_mic-mute-traditional-play-toggle : media next button unmutes media previous mutes
3_mic-mute-compatibility-volume: play pause button from bt headset toggles mic
4_mic-mute-compatibility-play-toggle: hold Volume + or hold volume - on your bt headset to mute or unmute.
I hope one of these work. For me, compatibility variations worked on my bt headset but only when I wasn't using the mic ( meaning mic icon wasn't visible in the system tray ). Whenever I was using mic, pressing buttons didn't do anything. But then my headset has mic mute button and maybe the button inputs aren't sent to windows when mic was in use in my headset case.