Need help with Clouds | Preformance | sun

Hey,im having some problems. the first problem im having is where you can see the sun trough the skies, so when you look at the clouds you see a small yellow disc. and how i can make the clouds more visible at “night time” ? i also get heavy fps drops from 120 to 60, the most important part is the fps drop.

here is the material if someone wants to look at it