Update? 

 This will probably take up my Sunday to resolve

Everything else is on pause. I have at least one copy of it for sure, but it will take time to run the search.

Second option will be more hacking involving possibly modifying a wallet search tool that already told me on both disks there are dozens of copies.

I mill find it. At least one copy exists of the newest.  My worst case projection is I lose the newest utxo or maybe two newest. That will hurt but not so bad as allp 

 You got the .dat file? What else is needed? This is all new to me. After you restore the wallet, can't you fetch addresses until you find all the utxo's? 

 The dat files I found already are ancient, they don't have anything current 

 So sorry to hear… I also lost some bitcoin this way when I first got started with bitcoin and was using Bitcoin Core, because I didn’t have a hardware wallet yet. It was quite a hard and off putting lesson 

 Update on progress, currently duplicating the main disk where the original was located. Soon will have two copies of both drives meaning I can restart the process if I fail somehow during the recovery

I'm really leaning towards starting with a tool that scans the raw volume and dumps what should be the full wallet file plus extra bits after. So far not having the greatest success with testdisk but once this is done copying I might try on the backup disk anyway, just haven't been able to make sense of the variety of disk dimensions it has been showing, like which one... Really just to have it scan from all filesystem roots looking for the file seems like what it should be doing.

I will explore the wallet file searcher first I think. At least see how it can be made to dump the possible files to disk