17 R5, unable to update BIOS ("Error: Unable to load driver.")

Greetings programs. I know this topic has been posted before, but this is a new, unique situation. Ever since I bought my Alienware 17 R5 four years ago (October 2018), I've been able to successfully update the BIOS using files from the Dell website (and the BIOS' "Secure Boot" was enabled).

I haven't updated it since 1.15.0 about a year ago (December 2021) so when I tried today with 1.20.0, I got the classic pop-up "Error : Unable to load driver". The only thing that has changed since my last BIOS update was the installation of Windows 11 this Summer. As a consequence, my Dell website's "Drivers & Downloads" only offers update for "Windows 10" (which was on it when I bought it).

I welcome feedback on how to push the BIOS update. None of the other solutions on this topic work for me, to include incrementally updating the BIOS starting with 1.16.0 or 1.17.0. Thank you and happy holidays!

--AFGP