It might sound a longshot but can you try with a different PSU? Sometimes graphics card noises can be linked to the PSU in use. It's NOT that the PSU makes the noise itself, it's just that the quality of voltages coming to the card can make a difference.
I don't wanna use frame limiter in CS GO.
I know this will be one of those gamer things that playing with less than 5 million fps makes the game anecdotally "unplayable" (we used to play Quake comfortably at 20fps, kids these days are spoilt
) but if the noise is that annoying, can't it be worth trying?
In league of legends I don't have any problems even at 400/500FPS.
I doubt that game is going to be graphics limited but CPU limited. Higher framerate in anything generally means the CPU is under higher stress than GPU. If the graphics card won't be under anything like the load it would not be much of a surprise for it to not squeal as if in pain.