I do have an active ticket with Dell but have not gotten any solutions yet. Update December 8 =There was no real resolution, more of a workaround. I had to do a fresh install of Windows 10 20H2 and then reinstall all the Dell software. I was able to get the software installation key from the Dell Digital Vault to reinstall.
I pulled 2 brand new 7400 laptops out of a box and neither will upgrade to 2004 or 20H2.  I have to believe others are having this issue?  Anyone figure out what is going on?  I get the standard error, "What needs your attention".  This PC can't be upgraded to Windows 10.  Your PC has hardware that isn't ready for this version of Windows 10."
Latitude 7400, cannot install anything after 1909