Product defect is a bit tricky. It's like saying a certain game crashes on an AMD GPU due to a faulty driver or poor game optimization. One cannot blame the buyer for this, what if they seller never played that game.
With regards to testing warranty, if that was offered, this would indeed be in your right to return.
Yes there was testing warranty and i have highlighted no internet connectivity issue on the first or the second day itself..
Reg your game and gpu, thats not a like comparison. Here its like the gpu crashes multiple times even when displaying simple things like desktop and movies