Test footage with HERO9 Black and the Max Lens Mod. Captured using pre-production hardware and firmware, so not final image quality.
Just chest mounted, so not hugely exciting, but I hope it gives a taster.
I don't shop at Walmart. I'd probably find something that worked "as-is" from McMaster-Carr.
I'd also be annoyed at having to do any of this on a $2,000 purchase, and would probably swear never to be an early adopter again.