Why do my keyboard and mouse work outside of Windows 11, but do not respond once the operating system boots, even in safe mode?

My computer is exhibiting a strange issue: The mouse and keyboard do not work in Windows 11, even in safe mode, but they work everywhere else: WinRE, Windows installation media USB, BIOS, with other computers etc.

Not even the caps lock light on the keyboard turns on, not even in safe mode. Is this a driver issue?

I don’t want to reinstall Windows, lose my data, settings, or installed programs. How can I go about fixing this?