XPS 15 9570 Gaming lag

Hello there!
So I bought a XPS 15 around 6 months ago and it worked perfectly fine. When I played games like Mine craft or something, I'd get around 120 fps. I even used to run you tube in the background.
But recently, The performance dropped drastically. Now I get around 30 fps with low settings. This isn't happening only to one specific game. I have the same issues with CSGO as well.
So I went online and researched a bit.
Tried updating BIOS,Intel drivers, Nvidia drivers,
Changed my default processor to Nvidia,
set performance to high in Nvidia settings,
Reinstalled both my graphic drivers using DDU.
No improvement in performance.

This has been happening to me for the past few days actually and I'd like to get it fixed. Please help.