Heating problem please solve this issue

Video calls use a lot of process power, which will produce more heat than usual, and the active display adds more temperature to that.

Are you using a case around your iPhone? If yes, take it off, to provide more cooling for the iPhone. Dimming the display a bit might also help to reduce the temperature inside the phone.

Did you already install the latest iOS 17.0.3 update?

Have any parts of the hardware been replaced?

Are you using a cellular connection or Wi-Fi?

Are you making a phone call through your carrier, or are you using an app to call, for example FaceTime ?

Try to connect, using Wi-Fi instead of mobile data and see if this reduces the heat while on video calls.