Just as the title says. The literal day after the warranty period was over, the backlight stopped working.
Microsoft told me, on the phone and at store level. “You should've bought the extended warranty. Buy a new one, right over there!”
The screen still works, as does the touch screen. I hooked up an external monitor, nothing wrong in the BIOS and Windows. Just the backlight doesn't work.
So I ordered a replacement from ifixit. I swapped the screens, and same issue with a brand new one!