It's been two days since I've noticed that my phone doesn't reach a full black color for the screen anymore. The darkest or closest to black it can get is a dark brown color. When I set the brightness to too low, the screen gets a yellowish tint on a white background while if I set it to too bright, black gets brownish and white seems okay. I dont know what happened but I've tried some solutions I have found online but didn't work. So I guess I can assume that this is a hardware issue?
This might help, or not, but blue light filter might be turned on. It makes the screen tiny yellow so it helps your eyes. Also, it could just be with how the panel works. For example, an amoled panel have deeper blacks, because those cells turn off.