Why Is My Screen Flickering?

I purchased a brand new Moto G6 (XT1925-12) from Verizon less than 30 days ago. Within 2 weeks my wife was complaining that the screen constantly flickers and rarely gets bright enough to see unless you are standing in the dark. After messing around with it a while I realized that the screen even flickers during shutdown and boot up. I even tried a factory reset, but the problem continues. Adjusting the brightness slider seems to have no effect on the brightness, and if I disable adaptive brightness that doesn't help either. I thought I would take the phone back to Verizon to see about a warranty replacement, but when I pulled it out of the case, I realized the back glass is shattered. My wife says she has never dropped the phone and it always stays in its case. After some more googling I found dozens of threads where people have said that the glass breakage is caused by exposure to temperature above 100 degrees especially in high humidity. Whatever the case, does anyone know why the screen flickers? Is there anything I can do to repair it?