Designer and stylists are different. with some overlapping areas

Designer create designs, with some outfits Planned in their head. Designer needs to be creative But also with technical knowledges and fabric / color/ print and embellishment knowledges in their head.
Stylists put designs together. Including clothes. Shoes. Bags. The whole Image.
Most designers work with a stylist to create their fashion show. Stylists enhance designer's designs and make them look crazier and more interesting.

My friend is a stylist. She would put all designers work together and then put together these outfits for catalogue. Pick location and pick models.

Anna Sui was a stylist when she starts. Most designers do not do both these days.

But small designer might need to be both. :)