Well, this is REALLY BAD. I left my laptop (batch 4 DIY, LUKS-encrypted Debian 11) off during holidays, I now need to do some urgent work and it doesn’t turn on.
Happy New Year, I guess.
Edit - Apparently BIOS 03.07 which is now available solves this (while possibly preventing your laptopt to boot-see below). Batch 4 shipped with BIOS 3.02. May I suggest emailing owners for this type of bug and update ? - Apparently an email was sent about this - just not to all users !
Edit 2 :After the BIOS update, it won’t boot - my WD Black 1TB NVME is not found. This is apparently fixed with (yet another!) firmware update which can’t be done unless you have a full Windows 10 on the same system (WD dash control also requires Internet) 
Spent most the day installing Windows to USB - only managed to do this with WinToUSB free edition on another Win 10 system.
Edit 3: It seems EFI on the NVME was zapped when BIOS was upgraded by USB/EFI method, I was able to restore it by following the GRUB EFI reinstall guide at the Debian Wiki with some variations. See this thread for more details.
In the end I spent 2 days chasing after this and getting back the laptop working again.
I had good recent backups, restoring to be able to boot again was the last fun part and worked. Thanks @another user for the hint! Never ever suspected the BIOS USB/EFI upgrade method to bork my system like this in 2022.