Question PC Trouble (super weird issue regarding GPU) help if able to

Jan 6, 2023
Hi, if you are reading this I hope you can help me find a fix for my friend's computer. The issue is when he plays any heavy title specifically Cyberpunk his computer will black screen and reboot showing the motherboard load screen. (However, his computer doesn't shut down and all lights stay on). I have run tests on both CPU boss and 3D mark and the only one to cause any crashes is 3D mark (if that helps). Every time the pc reboots, it flashes VGA on the board. One thing to note is when I tried different display port cables, some would consistently perform better (by lasting longer before the pc crashed), however, I have no idea why this would affect the issue in any way. I have replaced the power supply from a cx650m to a cx850m, changed the way power cables are positioned and used two cables to power the card. I then tried changing the motherboard slot hoping to fix it but to no avail. We were so fed up that we bought a brand new founders edition 3060ti but the same issue still happened! I have tried moving the ram sticks and testing each one and they still lead to the same conclusion. I have tried downloading and redownloading the NVIDIA drivers countless times as well as re-installing the Gigabyte GeForce drivers to help too. All of his parts were bought brand new and have had no issue until recently and we believe it's haunted at this point. I have heard it could be the motherboard but at this point, we want to sell it and rebuild a new pc or buy a pre-built. We don't know what went wrong and this pc suddenly crashes out of the blue and only under games. I truly thought it was the GPU but when the new card still gave us the same issue I wanted to give up. I have the pc specs displayed and will be looking at this forum every day until someone can reach back and help. I really want to fix this computer for my friend so we can go back to playing and so he doesn't have to spend his money on another one. Whoever and whatever can help this pc would be amazing.
Thank you,

Ryzen 5 5600x (not overclocked)
NZXT x53 kraken liquid cooler
G.skill TridentZ RGB Series 16gb DDR4 3200 mhz
MSI MAG B550 Tomahawk Motherboard
Corsair CX850M
Samsung SSD 980 500GB m.2
2 TB Hard Drive
AORUS Geforce RTX 3060TI 8GB