iPhone 11 Pro Max Screen Glitch Then Died

I purchased my iPhone 11 pro max new in 2019. Two weeks ago the screen started flickering crazy colors and then suddenly died. The phone was still operating without the screen as messages would still vibrate the device, find my iPhone worked and emergency calls went through, just no dispLay. I ordered a replacement OEM refurbished screen and it also flickered upon installation. After about 15 minutes it stopped and everything looked normal for about 3 hours. I didn’t glue down the screen because I wanted to verify resolution. After 3 hours the screen began flickering again. I have no idea what is causing this and the phone repair shop here in Germany also looked at it and don’t know. Anyone else seen this issue??