The app just doesn't open! I press open, open with admin, whether it's from Github or from itch.io, it doesn't matter, it doesn't do anything, doesn't even show up in task manager and windows protector isn't blocking anything. I really am not understanding why.

Try re-downloading first, but if that doesn’t do it, shift-right-click in GMEdit directory, pick “Open PowerShell window here”, and run GMEdit by typing

.\GMEdit.exe

and pressing Enter. That should give you an error message if it fails to start due to something on my side.