how is it possible to recreate the look for this site where they’re able to show two different textures?
You can use coords of a pixel in NDC to paint the parts of meshes by functions (circles, rectangles, blobs of noise etc.)
Pretty similar to:
Two different textures? Here is an example with polka dots amoeba over artish painting. The code is long, because textures are generated procedurally. The ideas is to have two objects one over the other. The top object has a dynamic alpha mask.
@prisoner849 Your solution is also interesting