Yes. So most of these corrupt file issues are recoverable.
However, a 320MB .aup3 file is the same size as an empty Audacity project so it is highly unlikely there is any useful recoverable data contained within it. If your file were 320GB or 3.2GB this might be worthwhile to persue.
There is a Corrupt Audacity Project Recovery procedure here: Corrupt or Otherwise Broken Audacity Project Recovery. It will recover Windows and MacOS projects, but the recovery process must currently be run on a Windows machine.
Again, since your project is only 320MB it is not even worthwhile to try (in my opinion).