I am also a heavy gamer. I usually play nova 3 and MC5 multiplayer games. Till now in terms of gaming performance the phone is beast. My maps load faster than any other player in the game. No frame drops at all. Also I am getting continuously 7 hours of gameplay in 100% battey. The highest temperature phone reached once was 45°c.
I noticed that if you play high end games without clearing the ram or downloading something in background then the phone may heat up. Those who are complaining about heating problems are the ones who dont know how to use or maintain a smartphone properly. NEVER USE ANY SMARTPHONE WHILE CHARGING IT! Never!
Also if u use mobile data( 4g) +fakewifi( root) the phone may heat up to 43-45°c