Hi @Marcel, welcome to the Blue Robotics forum 
While Blue Robotics do contribute to QGroundControl, we are not the primary maintainers of it, and we only provide support for it for use with the ArduSub flight controller firmware, with BlueOS (or our older Companion Software) running on the onboard computer (in an underwater vehicle). Generally that involves a tether rather than a radio transmission system, so we have very limited experience with using QGroundControl with radio transmitters.
I’d suggest looking at the QGroundControl support documentation to find the most appropriate place for the support you’re after.