FPS drops due to clouds

Hello, I wanted to send my report about my problem opening Minecraft. When creating a new world, the map is generating automatically, but now the game is running slowly and the fps is dropping. I don’t know if it’s the new fog in the game or a technical problem with the world.
When I downloaded snapshot 25w19a, I was normally generating a normal world and the fps was at 56 normally I suppose. But when I launched the first snapshot 25w20a and downloaded it, now when I enter the world the fps drops and it reaches 8, it's slow. I don't know what's happening, to be honest.