I had the issue that the USB-C ports on my Lenovo ThinkPad X1 Carbon Gen 8 all of a sudden did no longer work. I tried everything like removing the latest driver updates, reinstalling all the Lenovo drivers, did a BIOS reset etc.
I then did a battery reset (there is a small hole at the bottom of the ThinkPad which you need to press with a small pin) and voila: Everything worked again …
So if you have a similar issue, try that before sending your ThinkPad back to Lenovo for a mainboard replacement 😉
Lenovo ThinkPad X1: USB-C ports no longer working