iPhone X Heating & Hangs

I bought two iPhone X two months ago and gifted to my brothers. I returned home after two months and noticed that both phones get heated up after playing a game for 10 minutes, watching a video of 5 to 7 minutes as well as it gets heated while using Maps. One of my brothers phone was hanged for upto 3 hours, they had to keep phone in airconditioned room under 18 degres celsius and it started working. But still both phones heats excessively. What could apple do in this regard? I didn't pay to buy phone which I can not use for playing games, watching videos, using emails, tracking my road trips.