Strange FPS Behaviour of my PC

Hello everyone,

I've got a 8700k @5ghz with Kraken x62, 32GB 3600 Mhz DDR4, x2 500GB SSD and an RTX 3080.
XMP etc are on with dual channel. Also Windows 11 with every driver etc updated. Rendering API is Vulkan.
I've realized something strange while ago about the in-game performance. Whenever I go and check a treasure in-game, if that chest has lots of items/sets in it, the fps starts to drop until 90-120 from 144 then it cannot recover itself from that point. But then whenever I go to video settings and press "Apply" without changing any setting, the fps drop and stutter goes off. The same thing applies for the matches with a chance of %75. Whenever I feel FPS drops, I go and click "Apply" and it gets fixed for a while.
I want to know the logical explanation about this situation.
I know that my CPU is not that high tier anymore but I guess i should get a solid 144 FPS without drops in 1440p with my config.
I'm also open to your suggestions about getting rid of the stuttering and drops.

Thanks in advance.