the lcd is probably dead. the cable might have been damaged when whatever object got lodged in it or it could’ve damaged the inverter. either way what kind of geniuses do they have at apple that they didn’t consider an lcd replacement? did you notice the screen connector/wire when you opened it? Maybe the connection came loose since they are extremely delicate. I say check the video cable/connector and see if it looks like there’s any physical damage on the screen itself, front or back. I saw this a lot in my repair business. It could be as simple as a loose connection to a dead inverter, which you’d have to replace the whole screen. Hope you can fix it!