Welcome to the game!
I also love high fantasy style, but I haven’t build something to that scale so far. Just single buildings:
For “white” colors, I can recommend Ashen Blue Sedimentary from Minorengle
That’s the “white” rock color we had in the beta universe. It works quite well, I use it for signs and Shop Stands.
Cool Violet from Alder and Cool Slate from Gellis or Niia Zed Ka are brighter but the color tint shows a bit more.