I just did an interesting experiment. I took every available Apple device in my house, and put the settings exactly the same. Tried with TrueTone on and off. All next to each other full brightness.
iPad Mini 5, iPad Air 3, iPhone XR, iPhone 11- all different models and devices... the white point looks very similar and almost impossible to tell there's difference in person. The iPhone 12 Pro Max, not so much... it stands out bad...
Yet Apple claims these are to spec.
Below: from left to right, iPad Mini 5, iPad Air 3, iPhone 12 Pro Max, iPhone XR, iPhone 11. The one sticking out like a sore thumb is the 12 Pro Max, and while it looks reddish in the photo, it's just white balance from camera being off. It appears very yellow/green in comparison to the others- which are very consistent across the board.
Edit: Forgot to mention. The phone I used to take the photo was an iPhone SE 2020. I laid it down next to them all with same settings and it also appeared consistent with all but the iPhone 12PM, but... needed it to take the pic so couldn't include. :)