iOS 13.6 update - unable to access phone settings. Phone rings and nothing shows up in the screen

I just updated my iPhone X to 13.6. I wanted to unblock calls from non-contact callers and when I go into settings / phone nothing shows up.

i also just got a call and nothing showed up on my screen - just a blank screen and could only pick up the call through my headphones (function).

what else is broken with this update? How do I fix this?