When I change the system audio output while playing Minecraft, Minecraft is not adapting this change. For the change to happen I have to restart the game (not the Launcher).

I saw that there is already a simmilar Issue (https://bugs.mojang.com/browse/MC-180869), but it is stated as resolved.

 A solution would be to manually change the audio device in the Minecraft audio settings.
That would solve many problems and detecting a change in the system audio output would not be required for the solution.