Pretty much one year old issue, known to microsoft. I did a bios flash, the second one on this motherboard but was the first bios flash after license transfer from an old win pro 10 pc. I read of a workaround just too late to test it (disable tpm, login windows, change pin as requested and just after this procedure should be safe to flash bios from now on)
I read many posts of people asking support after this issue, since z690 chipset motherboard. The lack of support from microsoft, as we stated too many times, is unprofessional and embarrassing to say the least, and according to a tech south-african freelancer (Pyburn if you're interested), microsoft find it easier to crack a genuine license that present activation issues than just solve the problem...
Well, you can solve the problem the same way with the same tool, maintaining you're retail version of the license. That's a fact, don't ask :)
It's a 3 minute time fix, instead of waiting 3 weeks for a non-existent support, and it's suspicious that they cancelled phone and live chat support just at the same time this problems arose. Coincidence?