Half my screen malfunctions from time to time

The left half of my screen (it’s literally the left half, the vertical division is perfect) malfunctions from time to time. It works fine but after some use, it starts suddenly showing gray noise (gray/black/white dots) and after a while turns back to normal.

Sometimes instead of showing noise, it distorts the image, and again, after a while turns back to normal.

The touch works fine, and the right half of the screen works perfectly too.

I have disassembled the phone to check if there’s a loose wire connection but I haven’t found anything.

Any other ideas?

Thanks in advance!