This is a slightly different solution to the issue and may not be suitable depending on the desired effect. However. Interpreting the question as “how do I hide the lines on the top surface” rather than “how do I make the too perfectly smooth” another option is to enable the fuzzy skin option, which instead of smoothing the too layer will add a controllable amount of texture to the surface. I’ve not tried this myself yet but I have seen some really lovely prints using this feature and the prints have a really manufactured feel to them. It does however depend on the effects t you are after.