Windows 11 update killed PC

Few days ago Windows forcefully updated on my PC after a shutdown. It then proceeded to keep restarting for a day straight. Every time it reached Undoing changes... 1 second later it would restart, get to the same point and then loop like this indefinitely. If I plug in a Windows installer USB and select repair install, it instantly shuts off and boots up again. If I try to reinstall fresh, the drives are all locked with bitlocker. I unlocked and decrypted the drives. I copied over everything from ssd to hdd using the cmd notepad way (robocopy kept failing). Any repair or scan command brought no result. And now when I try to install clean windows on SSD, it just fails at 10 percent with no error displayed. "Windows failed to install" and shutdown. Deleting partition doesn't help, formatting drive doesn't help.

The drives work, I can see the files through the notepad. PC runs indefinitely in BIOS or installation menu but can't go through any repair or install.

What do I do? I dont know what else to try.