Not possible with current voronoi as scale is manipulating coordinates only. 100 bumps around the perimeter means also 100 bumps around the center. It won’t look right and you’ll have dual density issues, the closest thing you can do is mix up several rings of density. Like 10 in the inner ring, 50 in the middle ring, and 100 in the outer ring - that ends up with two duality/mixed rings.
Keep in mind the color ramp will introduce clipping for anything outside the usual 0-1 range. So if you use a certain good value for bump, then add 1 - the bump node will show no difference (because the gradient is the same) while using a color ramp will clip everything above 1 back to 1 leaving it flat. For various settings of the musgrave node, try previewing the bump node with and without a color ramp - musgrave is a good example of something that produces values one need to control.