Dang unfortunately I'm still having the issue. Project will open preview/debug maybe 10% of the time. I've even tried completely removing 3rd party Addon Effects and that didn't do anything. Here is a different error from the debug screen.
I know it's hard to help in this situation, but figured I'd let you know it's still going on. Deleted all cookies, allowed all permissions. Tried from different computers. Just pulling my hair out trying to figure out what's going on haha