Thinking about a GoPro, not just for sports but also for videoing my sons band…?

Mine works well, no idea about sounds quality though

I have and the image quality is pretty good. The sound does get muted if you have it fully enclosed though, so use the skeleton back if you want audio.

If you are videoing indoors then use the skeleton case.

Would be worth considering a gimbal to keep the footage as smooth and professional as possible too.

When I shoot bands I record the audio in a Zoom h5 with a second feed from the mixer if available. I then combine it in Premiere or GoPro app. The zoom h1 is pretty good too and costs not much more than the GoPro mics for sale on eBay.