By what you have described it does sound like the display cable connecting the monitor to the motherboard could be bad (a hardware issue that could only be fixed with a servicing). A screen replacement might not be necessary, only a replacement of the cable which connects the screen to the motherboard (but this would have to be determined by the service).
I have a 2.5 year old XPS 13, and when I am opening the lid the screen flickers and often goes so dim I can barely see what is on it. This used to resolve itself if I just wiggled the screen, but now the display goes dim if I open the lid more than 90 degrees. I called support, and they told me I would need to pay to have a technician come to me and replace the screen. Just wanted to check that this is my only/best option before I spend the money. Thank you!
XPS 13 Screen Goes Dim When Adjusting Lid