You should change your title to P47 Headphones is not being detected by bluetooth adapter
Does your bluetooth adapter work when connecting anything else to it via bluetooth? Need to know this to know if the bluetooth adapter is working in the first place.
If it is not working, please provide inxi -Fza so that we can see what bluetooth adapter you are using, and if you need to install a driver for it.
I personally could not connect my bluetooth headphones or speakers until I had pulseaudio-alsa, pulseaudio-bluetooth, and bluez-utils installed. Assuming that you’re using bluez for bluetooth.
More info: