Is it possible to downgrade to v126.96.36.199 or older?
Should be, yeah. Haven't done it with Hollow Knight specifically, but if you're using Galaxy:
-Click on the game in the side bar, should take you to a page that says "Play" in green and next to that is a "More" drop down menu
-In the "More" menu, go to "Settings"
-in "Settings" there should be a list of "Override Features" including Auto-Updates
-Uncheck the "Automatically update to newest version" box, that should make a list pop up of which version you want to revert to.