Things like this are indeed very frustrating and awful. I recently did an entire re-installation of my workstation. 3 Windows pro on metal installs, 3 Linux on Metal installs and 4 server virtualized installs. This took me roughly a week to get most everything
rebuilt to where I am now "operational" again.
The reason? A nasty memory resident, efi resident and firmware resident piece of malware I traced back to an UNPATCHED adobe font lib vulnerability. It's likely that this is a piece of Vault 7 kit that got out in the open. It's the most sophistocated thing
I've ever seen and I work in infosec and do this for a living. I even had to manually reflash my UEFI and firmaware on almost all of my hardware. It was the "super bug of super bugs".
All I can offer you from my expert advise. Run your on metal installs with extreme caution. I would strongly advise virtualizing systems that see daily driving use. (VMWare Fusion is my recommendation) This way you are in absolute control of system state and roll backs are simply a click away.
As to your specific problem. I think the non-standard way bootcamp passes in the boot loader broke a script in the update and it's either not finding a resource, or something to that effect.
- Try to boot into safe mode. You will have to consult others who use boot camp for more info. Try Reddit.
- Try sysrepair from a 1909 system iso usb stick and use the rollback feature. If this is broken or unavailable...
- You can try using Bob Omb's Modified Rescue Disk. This is a real winner for fixing broken Windows systems, I'm not sure about getting things like this to boot on Apple so follow the usual procedures for making boot disks for your system. Use EasyBCD or another BCD Editor. Modify your BCD entries to include one with safe mode and again attempt to boot into safe mode with networking.
If you manage to get the system booted into safe mode with networking run from elevated Admin console window
sfc /scannow
then run
dism.exe /online /cleanup-image /restorehealth
If nothing seems to work... the last option which is beginner friendly is Lazesoft Recovery Suite which has a number of automated fix options that attempt to solve all boot related issues. I reserved this as a last option because I don't particularly like
automated repair tools but I've tested it and it does work for fixing borked bootloaders such that I save it as a noob friendly option.
Moral of the story is that virtualization is a Godsend when it comes to system management and control. Use it for important things like work related VMs.