iPhone 15 Pro Max - Grainy Screen/Display

Hi! Just a few days after unboxing my new iPhone 15 Pro Max, I noticed that the display looked grainy, especially when looking at a white screen. I found that I am not the only one with this "issue", but I wanted to know if the screen is defective or if it's the normal behavior of the oled panel. Thank you in advance!

P.S. This is my issue: iPhone 13 grainy display - Apple Community

https://forums.macrumors.com/threads/iphone-15-pro-grainy-screen.2410069/page-2