13 Pro here, and after upgrading to ios17, I noticed my phone was running very hot, screen was dimming all the time, and battery life was suffering. It resolved itself a couple days ago. Sucks that we can't really get any visibility into what apps are causing the issues...can't exactly load a terminal and run top.
Kinda puts a wrench into Apple's whole "side loading apps would be a disaster!" thing...I mean even with the walled garden you have situations like this where they are approving apps for the App Store that have the potential to ruin the user experience with the device.
I believe this is a software issue though and not related at all to any specific chips or chip issues; at least it was for me.