Why I phone 15 doses not produce pure white colour on display

White colour looks a bit yellow on I phone 15 I have already turned off True Tone and night shift hence don’t get into that , somehow not satisfied with the colour produced by I phone 15 display it’s dull and bit yellowish my tft phone display was providing much more accurate colour as compared to this I phone 15 at least when it comes to proper printing, at first I thought it is problem with my phone but later checked with others as well including various version of I phone like 13,14,15 everywhere I found the same white colour being reflects as slightly off white. Can someone give a tft colour accuracy in I phone 15 I am not happy with oled vibrant colours