FPS 20 or 100 problem

Hi, so...
somedays I come to play and I am 20 FPS and somedays I am 100 FPS
When I say somedays its literally somedays, no matter what I do on that day, I will have 20 FPS, next day I just wake up and I am 100 FPS. I have no idea why this happens.

My setup:
Win 10
Ryzen 5 5600G
RTX 3060 12GB
32GB RAM DDR5 3200mhz

to avoid CPU Gap I am using vulkan, DX12 I have 100% of CPU in use, but with Vulkan it plays okay.

I used to play on steam and just 1 day on steam I had 100 FPS, I saw that if I download the launcher I would play it always faster. And I Did, but no, same issue. But I often play at 100FPS on launcher than steam.

I tried now to downgrade to DX11 and it works at 100FPS. But I could play with DX12 or Vulkan and get 100FPS but its just not often, which is... very weird.

if I enable lights, my CPU gets 100% in use, I have to have all of then in low. But no matter what I do, GPU is always on 100%


summary:
DX11 I have garantee of 100FPS
Vulkan sometimes I have 100FPS
GPU always on 100% use
Lights make my CPU with 80% use, vulkan helps a lot with it