On the left is the normal map generated by the Bevel node. On the right is an unbeveled cube with the Bevel node in action. I wish to convert this to a BW map where The edges/gradients are highlighted and the rest isn't. Does anyone know if this can be achieved with more nodes?
Final result and node setup:
After many tryouts with complicated setups it seems that this effect could be easily achieved by using Vector Math > Cross Product from Bevel > Normal output and Texture Coordinates > Normals.
After this the most efficient way is to use Color Ramp to change softness/sharpness of the edges.