Nice video I didn't even notice it in the first place
I'm not that much experienced with rendering, so I can't really say what to do. What you could try (if you didn't try it), is to make different texture maps, like specular map/bumpmap/displacement map. Like I said before, I don't know too much about rendering, but it seems like you only used a specular map, which gives the white reflection on the material. This looks pretty good imho, but with a bumpmap for example you could add a more rough look to the material. It might take some time to tweak the texturemaps to get best results, but I assume you already kind of figured that out
Btw, it also seems like the surface where the ball should land on has no collider, but instead there is a colliding surface under it.