Same here unfortunately. I received my 12 Pro Max recently in 2nd half of March 2021 and noticed the whites didn’t have that ‘true’ clean, dead-neutral white, which would otherwise help compliment all other colours as well.
Turning off True Tone doesn’t resolve the issue and with True Tone on, it’s oppressively overly warm making True Tone seem like a complete gimmick.
Experimenting with Colour filters deep within the Assistance Settings does not help in the slightest. The closest you might get is to have the tone level all the way to the minimum and try to slide the colour hue to what you may perceive as being close. However you lose some brightness output and you just can’t get it quite right with either a hint of red, orange, green or some other unwanted tint. Apple would have done better to have had separate colour sliders altogether along with a digital vibrancy and brightness boost if the final tweak was at the cost of losing some brightness and colour vibrancy (let’s face it you need all the brightness you can get in bright environments and sunny days).
But we shouldn’t have to resort to colour tweaking and attempted calibrating. This should have all been done at manufacture stage.
My old iPhone XS gives the most amazing dead neutral white that’s so neutral, it makes all other colours appear more balanced, more noticeable and pop. This is in stark comparison to the subtle urine-tinted whites of my new 12 Pro Max display.
Its really difficult to stomach on a 1,400 price tag of a phone.