⬛ iPhone 12: Why is my phone screen suddenly going black?

My iPhone 12 screen suddenly goes completely black in the middle of use, even though the phone still seems to be running based on notification sounds. Pressing the buttons does not bring the screen back most of the time. Restarting eventually fixes it until it happens again randomly later.

This sounds like the iPhone 12 is still running while the display or display connection temporarily fails. Since restarting brings the screen back, try updating iOS first and check whether the issue continues afterward. Also test whether the phone responds to touch or incoming calls while the screen is black. If the problem keeps returning, especially if the phone has been dropped, exposed to moisture, or had a previous screen repair, the display assembly or internal display connector may need inspection. Back up your data before taking it for repair. Avoid repeatedly forcing restarts if the problem becomes frequent.