After screen replacement, there's one partial column of green pixels.

Hi

The flexible PCB you were taking about shouldnt break easy and along as you weren't too rough with it it probably wasn't your fault

I would try a OLED stuck pixel fixer video on YouTube just don't look at it and make sure nobody looks at it as it isn't good for your eyes or people who suffer from sensitivity to flashing lights and images, also make sure you let it run for a good amount of time

if that doent work try cleaning the connectors with isopropyl alcohol to remove dirt we can't see

and last but not least if all this doesnt work would contact google and ask them for some replacement parts because your OLED may be damaged internally

hopefully this helps

Thanks:-)