system troubleshooting

Hi guys. I have a system build by me a while ago. It's a i9 9900, Gyga z390 WIFI Pro MB, 32GB RAM Corsair Dominion 3200, GPU Nvidia 3070 Ti FE. The issue i have is that every time I start the game I usually play (WoT), as well as other games like RDR, games starts, I can play for 30-40 seconds...

(I'm not sure which category to post this under since I'm not sure which component is actually faulty) I'm having a very weird problem. For quick context, 2 months ago my PSU exploded killing my mobo. 2 days ago I got my mobo RMAed and bought a brand new PSU (current specs at the bottom of the...