I just recently got a Hero 7 black, and running external mic via the GoPro usb c adapter. I route it through the back and mounted next to license plate. I'm having a harder time wrestling with race render, making the smarty sound real smart!
Here's the exact setup
Olympus Stereo Mic:
https://www.amazon.com/gp/aw/d/B000B...b_b_asin_title
Dead cat wind cover
https://www.amazon.com/gp/aw/d/B00HX...b_b_asin_title
10' extension
https://www.amazon.com/gp/aw/d/B00LM...b_b_asin_title