Interesting. I didn't watch his video, I just found it as a link to the rom.The guy in the video above has a video on making a repro Starfox 2 and he says you have to use Stunt Race FX or Dirt Trax FX
No idea if these 2 games use a different SuperFX chip to the other games or if they were just the 2 games that came to mind for him
https://en.wikipedia.org/wiki/Super_FX shows Star Fox 2 as a SuperFX 2 chip. Maybe it can be done on a normal SFX chip game as well?