Usually if you have a strip like that out its a broken LCD, but if you’re comfortable with it, you can always open up the laptop and reattach the display cable to see if that fixes it. You can find a guide here to help you do that (note that the guide I linked is for removing the top display, so you can skip removing the wifi card and antenna wires, and then stop after you’ve disconnected and reconnected the display connector).
If reconnecting the display doesn’t work, then its likely a broken LCD and you’ll need to contact support for a replacement. Be sure to remember that the 11th gen laptops don’t come with the cnc milled top case, so you shouldn’t be putting too much pressure on the display side of the closed laptop, as there is a chance that doing so will break the display.
Either way, hope you can get this fixed!