Audition Backup Files incomplete -- work lost

Hi

I have been assembling a podcast, with 8 tracks, including a heavily-edited interview, some rather clever sound effects and music segues.  We just laid in a VO track using punch-and-roll, and it was all cutting together beautifully.    BUT....last night, when I was about an hour from completing -- the project just vanished.   No spinning beachball, no warning.   As if a witch had cursed it ...  poof.  

I confidently restarted Audition and sent in a crash report, but when Audition reopened the project, it was missing all the work done over the past two days -- instead of 8 tracks, there were two.  Two crappy tracks.

I started tracking back in my backup files and realized with mounting horror that EVERY backup file going back to yesterday afternoon was exactly the same.  The dates were off -- the imprinted date and time in the file did not match the "Date created" or "date modified" in my (old) iMac.  They were all the same small size -- 76kb.  

I finally callmed down and went back down the list of backup files, trashing all the 76kb versions  -- until I found an .sesx file at 156k, which does contain the eight tracks, but was created at  3pm yesterday, when the error apparently started compounding itself.  I have done a TON of work since then, which is not in this multitrack project, and every backup since then is the same, 76kb, 2-track file.  

I have a practice of renaming my session file with the current date and time, then saving to the same folder (all are located on a remote 5TB Media Storage Drive.  My internal drive is too crowded to handle Audition projects and media).    The project files seemed rather jumbled -- projects inside of projects, multiple backup folders within backup folders -- so something is wrong there.  I have autosave set to save every 3 minutes, with a limit of 100 backup files -- which obviously the program is not doing. 

The computer on restart was very sluggish and commands obeyed only after significant delays, so I  ran disk utility, Etrecheckpro, and CleanMyMac.  No major problems were discovered, except  limited RAM -- I have maxed out at 16gb.  But I shut down all other apps while running Audition, so that should not be a problem.

Once I found what is apparently the most recent back-up, I exported that session, with full media files, to a second external drive, where I will leave it alone.  

I am with some trepidation about to open the latest session and start rebuilding this episode, which MUST go up today.   I optimistically named it "recovery."

What precautions should I take, other than wearing a mask and social distancing?

Thanks very much.  Etrecheck report available on request.

Rob