I KNOW HOW TO FIX IT DUDE. Every Itch download comes with a Steam key. Go to download Among Us, get the steam key, install steam if you haven't already, put in the key, and hit play.
It's triggering migraines, epilepsy, vertigo and some other conditions for people ever since the big revamp of the UI in late 2019. In spite of knowing it's a problem since a few days after the update, the only thing Valve has done which relates to the problem has been to block access to the only safe workaround that existed.