So, I had the same issue with the 21H1, but I found a portable (USB) Windows 10 that I had and it agreed to boot. After I made sure to install the drivers for Thunderbolt and Intel and nVidia graphics from the PCS CD, I tried connecting screens with either type-C cable and I had the same result as with Linux, namely no effect at all and freezes afterwards. I think I have no choice but to send the PC back to get the port fixed.
