Thanke you,
needed to install “bluez-firmware” for one of the headsets to connect successfully.
Tried that, but didn’t help.
I also tried to connect another pair of headphones which didn’t work. There were two Pop-ups, first a notification that connection was successful, then immediately that connection was lost.
In the bluetooth manger I get the error: “Connection failed: No audio endpoints registered.”
edit: Installed ‘bluez-alsa’: no problem anymore with regard to connecting new audio devices. Though getting them to play any sound still doesn’t work. And I can’t find any helpfull information about the issue in journalctl (not sure though if that’s the place to look for…)