There was a guest forum elf helping for a while and he prepared a special Audacity program to repair .aup3 crashes. We should wait for another forum elf to come by and help as I don’t know how it works.
Meanwhile, do you have backups for your original recordings? Could you put the show back together again from the backups if you had to? You should have perfect quality WAV sound files of all original, raw readings or performances.
https://forum.audacityteam.org/t/failed-to-read-from-a-file-in-c-cant-open-1-36gb-file/62985/13
Koz