Dell G3 3579, Graphic Card Issues

Hi,

I bought Dell G3 3579 (i5 8th gen, 8gb RAM, 128 GB SSD, 1 TB HDD, Nvidea GTX 1050) for playing Counter Strike Global Offensive and laptop was working perfectly fine for 1 year. Now the moment game starts the fps starts dropping (earlier it used to give 120 fps but now 20 fps) and coz of graphic card the laptop starts to heat up. I checked with CPU Usage shows 90% and system starts to hang. Customer care representative made me run diagnose and the result shows that hardware is perfectly fine and they are clueless what is the issue. Please help me, what should I do?