Page with content AND posts of a certain category?

Example URL: https://www.tranquilitycomputers.com/professional-services/cad-drafting-design/mapping-exhibits/

I have created a WP site to showcase my portfolio of work. I have created pages with examples of my work based on specific categories. In addition, I have a blog page for my rantings and current projects. I came to realize that I have no way of creating a slideshow of my individual examples from these pages since they are just a list of pictures and text as far as WP is concerned. If I could extract each of my portfolio samples into an individual “post-style” entry, I could create a “featured” showcase at the home page to show off some highlighted jobs. The problem is that I want to do more than just convert my Pages into Categories because if all I had was a categories list, I would lose the ability to create an introduction section ahead of each of the list of examples.

Maybe I just need to create a post in each category that is actually pinned to the top somehow that acts as the “introduction” to each category? Anyways, I’ve been searching all over the place but no luck. What do you people think?