Lock-screen/signin screen bug preventing signin

When I boot up windows, I am now only ever getting a blank sign in screen. The lock screen loads without issue, the background loads without issue, the OS seems to load without issue, but I am unable to sign in due to there not being anything when I pass the lock screen.

The sign in screen seems to load, as it blurs the background, and all the options in the lower right of the screen load, but the account doesn't, and there is no place to input credentials.

It also doesn't seem to be loading anything in the background, as there are no confirmation prompts when pressing shut down or restart. However, when pressing shut down, the computer doesn't shut down. The screen goes black, and the fans briefly pick up, but wiggling the mouse confirms that nothing happened.

Restarting seems to work as intended.

Entering the menu I receive from shift-clicking the restart button, I am able to go into advanced options, but only encounter UEFI settings in the sub-menu.

I attempted to follow a guide to fix the issue, but the all the guides I can find seem to require access to the account, yet I can't do that.

I have not, personally, ever encountered this bug before.

I am running a "fresh" install on an SSD (1T), with a backup HDD (1T), that was only recently installed (within 3 weeks), and am simulbooting a Linux distro on an old(er) HDD (1T), if any of that is relevant; however both OSs were operating perfectly earlier this week.

I haven't updated windows recently, to my knowledge.

I will edit in any further relevant info, as requested.