Move your whole fortnite projects folder to a new location thats not in the onedrive user backup, like C:\Fortnite Projects
keep the last project you opened in a seperate place like C:\somename because its crashing the editor and has to stay out of the fortnite projects folder in its current state
you will either have to restore the last snapshot or make a new project, then copy any content over from the backup in C:\somename, but you don’t want to copy it all just the UASSETs, which you can copy and paste into the editor viewport, select them by date modified if you only need to copy over the latest changes. And check-in changes lots in case a copy/paste crashes or breaks something and you can restore the last snapshot.
open UEFN and if it doesn’t crash, start a new map then go to the editor preferences and add the new project folder location C:\Fortnite Projects to Project Folders