What's wrong with topology? (bad smoothing)

give this addon a try,works very well

but since your model is curved,i would try to make the edges to the outside more straight,not so triangle like.this could eliminate the height difference in the mesh,you have now.(best is to have the edges with same spaces at the outside,for a even curve ,like a part of a circle ,if this is what you want)

then apply the weighted normals addon,and see if it helps