IPhone 15 extremely hot while charging

Some activities such as charging or a lot of computational activity (e.g., video), generate heat. Some warmth is to be anticipated.* "Keep your iPhone, the power adapter, and any wireless charger in a well-ventilated area when in use or charging."** Read this article about keeping your iPhone, iPad, or iPod touch within acceptable operating temperatures - If your iPhone or iPad gets too hot or too cold - Apple Support