Screen repair gone wrong, can't find the culprit

Hi Fixers,

I recently bought a pixel 2 with a cracked screen with the intent of replacing it. I purchased a new screen as well as a new battery. When I plug in the new screen, the device buzzes (indicating it’s at least responding to the power button being pressed) and my computer also recognizes that a device is being attached - so it’s not completely dead. The screen sometimes does a very swift white flash but otherwise remains completely black. I find it somewhat hard to believe that the motherboard’s display connector is broken, but I am at a loss for what else it could be.

One more piece of info that might be important: I can start the device twice by holding the power button, after which I need to unplug the battery in order to get it to respond to me powering it on again. Not sure why this is the case but might be worth mentioning.

Thank you and kind regards!