The video I linked is someone else's experience, but the same exact issue, i've seen threads as old as 2017 and this bug is plaguing me out of nowhere only starting yesterday. I've tried all the cvar edits (forcing game to fullscreen mode yet it stays windowed), game mode registry changes, compatibility mode, reinstalling graphics drivers and updating nvidia geforce experience as well as their optimization feature. I CANT PLAY D2 NOW, PLEASE HELP.