Experiencing major FPS drop despite the counter displaying high FPS

As the title suggests, I’m experiencing major FPS drops in some of the games I play in specific sections of the map. The FPS counter I got from pressing Shift+F3 and my NVIDIA FPS counter on the top right display that I either have 100 or 200+ FPS, but in reality the FPS drops to completely unplayable levels.

The video:

Capping my FPS appears to solve this issue, however I want to know why uncapping my FPS may lead to this.

Edit 1: Fixing grammar.

My hardware:

CPU: Intel Core i7-14700F
GPU: RTX 3060
RAM: 16 GB

My PC should have no problem running this game whether I cap my FPS or not, why does this happen?