Glad to hear someone who knows 6500k chime in on this. After 10 years of calibration warriors trying to say this is simply moving down a bit in calibration its good to have someone who knows what they are talking about.
Id wait at least 6 weeks launch to try again
I'm just gonna keep mine since its only "warmer" not severely yellow tinted, and if they get better later I'll get the screen replaced under warranty. This may be the first year I opt for AppleCare.
While I was in the store doing the return, I compared my Pixel 3 to both a display 12 and 12 Pro they had at the table I was being helped at. Both were significantly warmer, so much so that I was thinking, "wow, I didn't realize how cold this screen is." When I got back home, I took a double-take and compared the P3 to my monitor and it was very close, maybe a tinge colder... I am kind of kicking myself because I didn't check to see if true tone was off, so that could've been why.
Either way, I saw the associate turn mine on and I immediately noticed just how dingy it was. I even asked her, as she processed my return on her perfect-white iPhone beside her, "Do you see that?" She agreed, if a bit reluctantly. I know true tone is automatically enabled on fresh start devices, but still...
Maybe there are some "good but warmer" screens out there, but mine certainly wasn't one of them. IMO, Apple's really relaxed manufacturing tolerances for this year.