Hey there,
as others have already pointed out, we get issues when trying to recreate the sand sculpture shader in Blender 4, which was shown in the lecture Sand Sculpture Shader.
As others already suggested, decreasing the strength of the bump nodes quite a bit helps, yet I was still having a rough time recreating the shader. I read a comment from Stephen in this thread that using mix color nodes might be a bit easier so I gave it a shot. In case someone is interested and facing the same issues, here is my sand sculpt material:
(You can download the images and zoom in if need be)
You can play around with the factors and blend modes on the mix color nodes to adapt it how you like, but I like the shown values.
Moving on to the next lecture, good luck to you 
Cheers,
Kevin