Though I'm not a crazy gamer, I do have a dig at Kingdom Rush and Defense Zone for extended plays when trying to kill time, and the Mate 10 barely gets luke-warm.
Compare this to my recently-retired LG G4 which got quite hot, or my worst (heat-wise) 'phone ever, the HTC One X (that thing felt like it was going to melt just by using Google Maps for a few minutes!).
Evidently when it comes to chipsets generating heat, Kirin is better than Qualcom is better than nVidia. Don't know where Mediatek slots into this as I've never played with one for long enough to tell.
I agree with you 100% , I had LG G4 and also Samsung Galax S4, and both of them used to run Super hot compared to my Huawei Mate 10 lite. The moment i turn on LTE 4G phone would get hot! Making it the worst phone to ever have ( Oh LG G5 is famous for chipset failure ). I was amazed with the difference and was really surprised, as Huawei is supposedly a less inferior brand, compared to monstrous Samsung who's popularity is sky high.
I contemplate as to what could the reasons be, and finally concluded it's the Core-Chipset , Unforunately, Snapdragon, Mali, Qualcomm , all the chipsets from these manufacturers runs Hot, in whichever Phone they might be in, S5, S6, S8, S10. Searching online mostly all phones with these chipsets are famous for heating up like a desert.
Now i am never going back to Snapdragon!