I don't know how these other vloggers use a GoPro so successfully, every experience I've had with GoPro products since Hero3 frustrated me. I feel for you. The latest DJI action cam may be a good alternative. I have never been disappointed with a DJI product from gimbals to multiple drones. They seem to be well engineered from the get go.
Sorry you're having problems. I've never had any problems with any of mine. I had 1's, then a bunch of 3's, then a bunch of 7's and 2-10's. I've never used a media mod though. I use a separate mic and audio recorder and sync them later. I'll take everybodys unwanted gopros.😁