Iphone 13 Pro - line across screen

Hi all, so i have anew iphone 13 Pro. The problem I have is that there is a horizontal line across the top of the screen. It´s brand new and hasn´t been dropped. I spoke to apple about it and they said it was a software issue transferred across from my old iphone, so I needed to do a full factory reset and instead of using my old icloud backup or transfer, i needed to install all the apps one by one. So i did that and as soon as i started installing apps again...boom, stupid line across the screen. I dont know what to do?? not sure if the phone is a dud or not. Because i started up my old phone and there is no horizontal line???

It almost seems like the new phone which has a bigger screen, still thinks that it has the smaller screen of the older phone....any help would be great, otherwise, a refund or new phone is in order.