ALRIGHT GUYS. I FIGURED OUT HOW TO DO IT.
First, you need to re-download Among Us.
Then, it opens up a folder, and there should be an Among Us folder that is labeled Among Us, so open that one
When you click on it, it'll ask you if you want to "extract all". Click Extract All, and it'll start extracting. After that, open the app FROM THE FOLDER (that's what I did), and it should be working fine.
I hope this helped, I understand the dillema all of you are going through if you bought the game on itch.io. c: