I do believe the iOS 17.0.3 update has fixed the heat issue on my iPhone 15 Pro Max . It now tracks what I remember from my 14 Pro Max in terms of warming up, and in fact may be cooler.

It’s also worth noting that I’m an Instagram user (gotta put those cat photos somewhere!) and that was also updated for its own issues on the 15 Pro models. So overall, I’m calling it a success, for now.