You might also feel something wrong while looking at its screen, like viewers of other OLED display are. Apple is making your expectations slightly down by laying out a whole support page on its website regarding the panel.
Certainly, it has a 1,000,000:1 contrast ratio with wide-as-heck colour gamuts and HDR10 and Dolby Vision to boot. No doubt, it’s better than industry screen, but it is also causing colours to shift and burn in.
If you look at an OLED display off-angle, you might notice slight shifts in color and hue. This is a characteristic of OLED and is normal behavior. With extended long-term use, OLED displays can also show slight visual changes. This is also expected behavior and can include “image persistence” or “burn-in,” where the display shows a faint remnant of an image even after a new image appears on the screen. This can occur in more extreme cases such as when the same high contrast image is continuously displayed for prolonged periods of time. We’ve engineered the Super Retina display to be the best in the industry in reducing the effects of OLED “burn-in.”
The company also mentions ways to increase the life of the display like updating iOS regularly, relying on auto-brightness, leaving the display off when not in use and not letting motionless images remain on the screen at maximum brightness for a long time.