I have two physical drives in my PC, one is the system partition and the other is the boot partition. I unplugged my system drive and rebooted my computer, but it complained that BOOTMGR is ...

That's not a viable solution though. It will boot with the 3080ti plugged into nothing, then plug in the TV via HDMI after its booted. Again, don't really want to plug and unplug my HDMI every time.

If your Windows 11/10 computer is connected to a second hard drive and you find that it will not boot under these circumstances, then this post will help you.