Not sure what to do at this point.
I had what I think is a similar problem with Mail. Couldn’t resolve it so I erased the drive, reinstalled, and migrated from my backup during the setup assistant. I’m my case, it was failing to display emails and quitting Mail because there wasn’t enough space.
A temporary solution for me was to delete all local snapshots created by Time Machine.
Copy and paste this command into Terminal to clear out any local snapshots.
tmutil deletelocalsnapshots /
That might clear up some space that isn't reported as being used.
Open Mail and see if it will import.