Does the BT device show up in Settings-System-Audio?
If not, have you constructed a .asoundrc file? (note the dot .) It should look like this:
pcm.kefmuo {
type plug
slave.pcm {
type bluealsa
device "40:EF:4C:CC:DE:9E"
profile "a2dp"
}
hint { show on description "KEF MUO"}
}
If you type nano ~/.asoundrc you can cut and paste what I’ve typed above into that file - Ctrl-X to save and exit.
Then restart Kodi with Power-Exit.