Can a spray sealant or quick detailer reduce my ceramic coating's water beading?

It can. Many spray products leave their own layer on top of the coating, and that layer then determines the water behavior and feel until it wears off. Because a cured coating repels most products, many sprays do not bond well to it and wash away within a few washes, so any change is usually temporary. Products containing gloss oils, waxes or fillers can make a coating bead less or attract more dust, while toppers designed for ceramic coatings bond better and tend to support the coating's behavior. If beading changed right after using a new spray, wash with a coating-safe shampoo and reassess.