Question Help with PC Rebooting After Loading into Game!

May 24, 2020
Please excuse poor formatting I am new here :(

Ryzen 5 3600
GeForce RTX 2060 EVGA
Corsair Vengeance LPX 16 GB (2x8GB)
Corsair CX Series 750 watts 80 plus
MSI B450 Tomahawk Max
WD Blue 3D NAND 1TB SSD M.2 2280

Over the past few months I have been trying to solve the mystery as to why my PC reboots during some games when I load into a match. It tends to occur on games running at higher graphics settings and would occur more with V Sync enabled. For example on CSGO it reboots my pc as soon as I load in a make a few movements.
I have already tried the following:
Testing both ram sticks individually to see if either makes a difference on it’s own.
Replacing motherboard with a refurbished one.
Using a different GPU.
Updating Bios.
Checking and disabling any Overclocking settings that may have been enabled (although I have never overclocked my cpu).

I think that leaves only the CPU and the PSU left. I have tried using a benchmark program to stress the CPU and it doesn’t cause it to crash which leads me to think (although I may very well be incorrect) that the issue may not stem from the CPU but rather the PSU.
Are there any other tests that I can run to try and diagnose my PC?
If I have left out any information necessary please let me know and once again I am sorry for any formatting or etiquette mistakes! Thank you!