Hello,
I am also one of the countless victims of this problem.
No luck, I don't have an apple store in my country and because of the lockdown, I can't send it to another country.
So I went to a professional apple repairer and I changed then screen with a new one.. but the problem returned again a few days later.
I went back to the repairer again who was surprised, we thought at the beginning that the problem came from the new screen (manufacturing defect), he then changed the screen again with another new one ...
But again, a week later, the horizontal lines reappeared below the screen especially when I plug it in with an external monitor.
This is where I discovered this topic and I get to better understand the problem.
But my question is: Why does changing the screen not solve the problem? knowing that those who have changed the screen at Apple no longer have problems? Also, are the 2 new screens are actually really damaged for good ?