What's the "heating issue".
My phone occasionally gets hot. I can usually trace it to some intrusively rude app(s) in the background trying to run or refresh and also when am in an area that connections signal strengths are weak. Meaning cell, wifi, and bluetooth.
What works for me is to turn off all apps background refresh. I also off device connections not using. Eg, turn off the wifi and bluetooth when I leave home. If these are left on and the phone senses connectable devices nearby, it will keep on pinging and pounding on them to try to establish a connection. If not a connection that you have pre-configured, then it fails then tries again and again and again. Leads to heat and high battery drain.