Older projects crashing Musescore 3

Back in September I was commissioned to arrange show choir music for a local school's competition season... I finished it but some of the music need to be edited or cut completely due to length. Last Sunday on the 19th I met with the director and he gave me a short list of what to cut. I went home, made a copy of the original file, made the cuts, and it saved them like normal. The next morning I went back in to make final adjustments and Musescore repeatedly crashed every time I tried to save my progress or tried to export it. I ended up going back to the original file for the edits and doing some copy, paste, export as a PDF magic so they had the music before their show reveal on Saturday. I have done a factory reset on Musescore, I've reinstalled it, and I'm still have issues with it crashing. I even switched from my macOS version to Windows to try to open the files and it crashed the Windows version too.

Today I went to write in extra synth parts into the ORIGINAL file to export as a PDF as I did previously, but now both the original file and the copied file are crashing. I want to work on other projects but I'm too scared my new and old projects will mess up too.

I attached one of the files below.