I've got a Samsung Galaxy and I had the same black prompt screen -- for about a month. Then two days ago, the black prompt screen was replaced with the Enter Pin screen complete with a keypad that allows me to use my mouse to enter a pin -- or lets me just type the pin in my PC keyboard and press enter. In other words, everything is working normally again.
But to be clear, this normal operation is only possible if I have "phone-link-1-22102-202-0" installed and prevent the Microsoft Store from automatically updating this older "202" version to the latest Phone Link app.