Help with my hot phone :O

my phone heats up when i play making me get less frames, please tell me on how i can keep my apple iphone XR cool. Im trying to add more characters so it doesnt get auto removed... I got the phone for my birthday its is the red one, i have ios 13.5.1 (i wonder if i have enough characters now) my friends play fortntie with me, it is fun i enjoy playing with friends...

anyways incase you missed it my question is: my phone heats up when i play making me get less frames, please tell me on how i can keep my apple iphone XR cool