why does it need to ne smooth anyway ? until specific needs like sculpture, most people reaction to first contact with printed parts is " well, not bad look, it’s the look for 3d printed parts…that’s it ! " . For sculptures, maybe the FDM is just not the right choice and SLS or SLA would be better ? ( better for details anyway).
+Marcus Wolschon do you have me blocked by accident?
… or on purpose