Damaged and can't be opened :(

I ran into the same error today, and it’s affecting all my beta saves and autosaves. The only one I really care about is the project I was working on yesterday since it’s time-sensitive. I saw another post about the XML fix by @Yori X, but I can’t wrap my head around how to do it myself. So now I’m just wondering if I’m screwed or not. I also tried reverting to the previous version, but the app just crashes when I try to open the file.

Can someone help me please or guide me?

I guess if i manage to salvage this by tomorrow, I need to export everythign to XML and reopen and continue work on the stable version?