I have a bluetooth headphone with microphone and when I connect it through bluetooth I can hear the sound but I can’t use it as a microphone because it is not shown in Pulseaudio. Also HSP is showing unavailable. I’m noob in Manjaro KDE. I have used the same headphone in Ubuntu with HSP.
You can be connected either via A2DP (high sound quality, no mic) or HSP (low quality but with mic) profile. The A2DP is default.
You can to change the used profile after connecting in:
System Settings → Audio → Configure (button) → Profile (drop down list).