Here's a shader node group that generates a pattern that looks like those little ridges you see after the tide has gone out.
Made while experimenting, what you see is what you get: There are only basic inputs for Texture coordinates, Scale and displacement Amount; outputs for Shader and Displacement.
There are loads of things that could be added to make a general purpose sand shader but that would require a lot of nodes and create many inputs the would probably never be used. Basic changes can be made inside the node group.
Looks realistic compared to similar beaches I've seen. Well done.