If it has no face ID or true tone it would confirm it has had a replacement screen installed. People planning to sell their phone will opt for the cheapest screen to replace there broken one. With the iPhone X there are three screens you can choose from, an LCD, hard OLED and soft OLED.
The LCD screen is the cheapest and are not really designed for the iPhone X. I have not herd of a temporary fix for this problem. Without seeing any images of your screen I would make sure it is not a swelling battery that is causing the problem, 85% battery health can cause this. I usually recommend a battery replacement at 87%.
I would order a new screen and battery for this phone. There is not much else you can do.