Many people believe that it is easy to design landing pages and banners, while interface design is difficult. Any designer can make a landing, but only specialists can make a good product.
It is obvious that experienced ones are always better. And the weaker the team is, the more experienced the designer should be. But it is the landing pages that are very sensitive to a rare design talent: the skill to verbalize meaning and make up a story.
Landing is primarily a story, and only then a set of graphic blocks. It is probably not such a great idea to create a narrative first, coordinate it, and only then give it to the designer. You need to understand how the text will look like on the page, how it will interact with graphics, illustrations and interface elements.
It is better to compose the text right in the layout.