If the the USB-C of your GoPro is also a audio output then it should work. But if its just a Charging Port, then it will not work.
Better chek the manuals of your GoPro, im sure you also find the answer, if you google it
The producer does not seem to give any information on this
However, I assume that this should be possible.
If not, you should be able to return the product.
Hello Marco, this might be more difficult because, for example, the power supply on the 3.5mm socket is missing. This would require an adapter with battery. I haven't come across anything like that yet.