I wanted something like this, for example to grab the normals of the point, and surrounding, and if they are co-planar then it gives a 0 for example, and the further away they are from co-planar the closer the return is to 1
Use that number to lerp between two values, would essentially allow you to identify edges.
It wouldn’t be great flexible but would be easy in theory, but I’d have to learn how to code a shader I think