I ran into the same issue. In my case QB2021 crashed and the file wouldn't open after. I had about 6 solid hours work gone since the last backup. It was allot of work. I couldn't let it go so I started digging.
I happened to find a hidden directory that had quite a few backups, one about an hour before the crash.
In the hopes this helps someone else the path is:
~/Library/Application Support/com.intuit.QuickBooks2021
This directory for me is about 7.3GB but the files in there barely add up to 60MB. So I opened up PathFinder to see the hidden files and sure enough there were a ton of directories that start with a "." (so they're hidden by default). I opened the one that was closest to the crash time and sure enough there was a backup file in there and from the looks of it all the data was there.

For those who don't have PathFinder you can see hidden files in the finder by typing [command] + [shift] + [.] while in the directory -- That's command shift period.
Hopefully this helps someone else hang on their hard work.
-Mano