My iTunes Library is gone...

I recently updated to macOS Catalina without knowing that it had many different bugs and issues, and I also didn't know that when updating to Catalina, all 32 bit apps became officially incompatible.

Most of my downloads wouldn't work, but I decided to just wait it out and hope Apple fixed Catalina soon.

So here I am, a couple months later without any change. Normally this wouldn't bug me, but my iTunes library on the iTunes app vanished!! All my songs, stories, and podcasts all gone. I troubleshooted a little bit, and finally decided to downgrade from macOS Catalina to Mojave, but after watching numerous videos, I decided it probably wasn't the way to go, though I may revert back to that idea.

Most recently I figured out that iTunes could be found in the Finder App, so I opened it and downloaded all of my songs back to iTunes, my insides screaming, "Yesss I'm so glad I didn't have to downgrade!!"

. . . well, a message popped up saying something around the lines of, "the itunes library file could not be saved. an unknown error occurred. (-50)"

Apparently a couple other people have had the same problem, but none of the answers I found on the previous posts helped.

It took around an hour for the entire library to download, and then POOF, it doesn't work. Over 36,000 songs and stories gone.

Should I go back to downgrading from macOS Catalina to macOs Mojave, or will that fix nothing? How do I get my music back?

Lots of my apps are 32 bit too, which means they are incompatible with the new update...

So what I am basically asking is, what is the easiest and most efficient way to get my Library back, and at the same time get most of my apps working again?

Thanks in advance.