I had a new Win11 update and had to go through the same trouble, but I found the solution!
It appears that every Win11 update switches my computer to FastBoot. I have a graphics card, but the monitor was connected to an integrated graphics port, not the graphics card port. The BIOS video settings have 3 options - Auto (default), external and integrated. Auto prioritizes external card. Unfortunately, FastBoot is so fast, that the machine prioritization process fails - the machine does not realize that there is no monitor connected to the external card ports and keeps sending video signal there.
So to solve my problem, I had to find a HDMI-to-MiniDP adapter, connect the monitor to external ports, and either use that setup, or enter BIOS and change video settings to use integrated port. Or buy a monitor with really fast response rate.
This also explains, why I never had this issue on my laptops.