This was tested on Debian 10, running KDE.
I bought the following headphones: Coocheer ANC8.
I wanted to use them on a desktop machine running Debian 10 with KDE. Here's what I did:
- Since my desktop environment had not bluetooth capabilities, I bought the following Bluetooth USB Adapter: TP-Link UB400. Inserting it in one of the USB ports of my machine, KDE detected it instantly and activated the bluetooth capability.
After this single step, I could see my headphones on the list of available bluetooth devices but got the following error when trying to connect to it (seen in journalctl)
a2dp-sink profile connect failed for 30:21:07:9D:72:05: Protocol not available