Galaxy S6 turns off and on by itself and freezes constantly

[AC Question]

This phone... Every android phone I have ever had has always had some sort of problem that takes me to search google for hours for an answer. I always resort to this: posting a thread to get help. Now, for the actual problem (other than having wasted years dealing with android) My phone keeps freezing and turning itself off and on again, and again and again. I can't use my phone for barely 12 minutes before it either freezes or turns off and on again. I have cleared the cache- multiple times. I have also performed a factory reset.
This is my 3rd Galaxy S6 phone, and I don't think I've had this type of phone for a year. So, when I got this phone I made sure I followed every recommendation there was. Don't use the phone while it's charging, don't let it die, don't turn off the phone while it's updating, only installing apps that are approved. I haven't rooted my phone, or any of my phones ever, and I even make sure I look for answers before flipping out on Android. I keep my phone charged and turn it off when it's not being used. I even used the approved Samsung fast charger for my phones. I use the one the suggest but i still get battery problems????? My phone still over heats, my phone is still slow, no matter what I do. So please tell me how to fix it before I damn all of Android and Samsung.