Okay, just to say and maybe to calm a few people down. I picked up my iPhone 15 Pro Max 2 days ago and so far I can say that I had zero issues with it. I transferred all my data including all 324 apps from my old phone to this one and I didn´t noticed any kind of "extra" heat, it was normal. I also charged it the whole night using Magsafe and in the morning, no heat at all.
I also tried normal surf and a game. Nothing at all so far.
But I will of course try some other stuff, demanding apps and though games and so on.
The issues people say here might be related to some countries or something else, I really don´t know. I live in Sweden! Just wanted to say this so people don´t think the heating issue has do do with every phone out there.