I got it working after a whole night of nothing but testing.
Use Touchctl in shell, remove any trace of previously registered K83 entries and keep trying.
Eventually it will tell you to enter the pin.
Mind you i got it working with an Asus Bluetooth dongle i had lying around, i don't think that is needed but i simply dident have the patience for trying without after i finely got it working.
I don't know why it doesn't ask for pin every time but i seem to get it to every 10th or so try.
After it has been paired correctly there should be no problems reconnecting it again.