Yeah, since beta 1 people have been reporting some of these overheating issues with apps that have not been updated for the new OS. Meta slept on this for like 2 quarters.
Also, the hardware seems really unlikely if the pro and non pro logic boards are heating up (different chip, different enclosure material), as well as old iPhones and iPads running 17.
Looks like no one in the press decided to take a day to see if this was reproducible on other phones.