Unfortunately, it is not as simple as just plugging in the cables and hoping everything will work out together.
There is balancing electronically that needs to be done so it all works between go pro and aviation headsets and that is why you need to buy the correct cables like the XCOM one or you will be chasing yourself around and around in circles trying to get a professional job and any reasonable sort of audio output that can be used.
XCOM have sold more than 2000 of the cables over the past six or seven years with nothing but good reports from users.