Could you provide a little more details. Foe example:-
1) When you were playing PUBG and your phone crashed, did the phone continue make a beep-like sound after crashing
2) Did your phone fail to reboot on the first try whenever it crashed and you had to see the "Powered by Android" screen more than once?
3) Did you monitor the thermals of the device when it crashed?
As much a the little information provided indicates, you seem to be another one of the unfortunate users who got a faulty device (Myself included) and the best (and possibly only) option would be to file for replacement (if you're still in the window) or go to your nearest service center and ask for a motherboard replacement.