So I have a similar problem as many I've seen here. Running Win 10/11 upgraded pro perfectly fine. I haven't been able to get a few of the last updates, minor ones work, major don't. I downloaded newest win 11 iso and tried upgrading from a usb and mounted on my 2nd nvme drive (high end Ryzen 7950X system). What I also noticed after doing all the usual troubleshooting is sfc /scannow doesn't work at all, even in safe mode, only from repair CMD. It says
C:\Windows\System32>sfc /scannow
Windows Resource Protection could not start the repair service.
Some DISM commands work, some don't. Even tried disabling SVM in bios, no help. When upgrading windows to 23H2, it get to 100% on the blue screen then just drops back into windows with a little box saying it failed, no reboot or anything. But if I try a new install from iso/usb it installs fine, so it is not my hardware. Something in windows is preventing it from working, missing or corrupt files. Also have admin and my user as full control, tried installing from both. Same issue.
I downloaded SFC fix and await further instructions/help.
Thank you