I’ve not had time to get this up yet and I’ve got a little bit more to add to this, but here is some updated information for using Dynamic lighting with Cascaded Shadows . These only apply to Directional Dynamic lights and not to point or spot lights. This can help you understand how to get more refined shadows that are not solely by adjusting the shadow bias or the filter sharpen.
Hopefully that doc will help you get the shadow quality you want from the directional light. If you have any questions feel free to post any screenshots along with a description of what seems off and I can offer some help. 