Bizarre touch screen responsiveness

I bought a used HTC 10 that said it had a dead touch screen zone at the bottom of the display. Using a drawing app you can see there is a half inch tall dead touch area that spans the entire display. Visually the LCD works. The odd thing is sometimes it is dead and sometimes it works. On HTC's Android 7 and 8 the bottom half inch of the screen doesn't work on the home screen or in apps but it 100% works for the keyboard. I installed Nova Launcher and the touch area started working on the home screen but still didn't work in apps. I thought maybe it was an issue with HTC Android so I flashed stock Android 10. The dead zone is gone on the pixel launcher home screen and the keyboard still works but the dead zone is still there in apps. I thought installing Android 10 would eliminate any software issues but it doesn't seem like it would be a hardware issue since the touch screen works 100% on the keyboard and homescreen. Any ideas what the issue might be? Thanks.