I am looking for a new smartphone. I have had troubles with my previous phones: overheating and lag. I strongly believe that this is from the hardware, since I have been having these problems with my three latest phones, all Android, all flagship devices - a Samsung Galaxy S5, a Sony Xperia Z3+, and a OnePlus 2.
The overheating has occurred when watching YouTube videos and using Snapchat (which open and closes the camera a lot). The lag occurred overall in different places, including starting/switching from applications.
On the Samsung I did not have overheating issues, only lag, but on the Sony and he OnePlus 2, they both overheated a lot.
I am looking for a phone which can play YouTube videos without burning my hand, and which will not freeze (because of overheating) when using the camera a lot. I want it to run apps smoothly.
What should I be looking for when I go through the specs on different phones, and why?
I have been used Google to gather information about the phones. In my experience, I only find sites which say how "good" the phone is, almost like Samsung, Sony, etc have wrote the article themselves. In the past, I have trusted the information I read before buying, later finding myself fooled.
Edit After reading the comment by Alpha3031,
What phone would you recommend which will fufill the requirements: smooth running, reasonably fast for light tasks, and does not overheat? I do not have a limit in budget.