Screen Black After Update to macOS 11.4

MacBook Air 2019. When updating operating system thought I noticed a black rectangle flashing in the upper right quarter of the screen but when I moved the update box to the left part of the screen I did not see it. Then when it was restarting to install the update there was a thin amount of black flashing across the whole very top of the screen before it turned off. I came back the computer and now the screen is black. The keyboard lights up. When I turn off the computer by pressing the on button I can see the screen get blacker. It is a uniform near black when turned on. Only thing new is that I listed it on eBay with the serial number.