A look at the handrail into newel post assembly options in StairDesigner. You can edit all newel post to handrail links across your entire stair, or select one and edit just that.
You can add a penetration of the handrail into the newel post. And as soon as you add the penetration you can add further parameters: an upper recess (or cut out) of the handrail, a lower recess and lateral recesses. With the lateral recess, the cut out is applied on both sides.