The purpose of the CMS and Collection Pages in Webflow is to support large sets of same-shaped data. Recipes. Blog posts. Employee bios. Products. All of these pretty much contain the same shape of content and use the same basic layout.
Some types of pages such as a project portfolio are not as easy to fit into Webflow's CMS model because you may have very different type of information that you want to show for each project, and in a different arrangement.
If you have only a few projects, static pages is your best bet, and Webflow recently ( 2023-Q2 ) increased the number you can have to 150 static pages per site.
However if you have a lot of projects, or really want them in the CMS for other reasons, you can make heavy use of conditional visibility and rich text fields to create more versatile layouts.
This video and the cloneable demonstrate a way to manageably create 4 or 5 different layouts for a Collection Page, which will switch depending on a defined item type. In the sample of a project portfolio, think video project, website project, product design project, branding project...
Note that even though I designed this technique for a client website, I use it very rarely. Basic conditional visibility and a well-thought choice of CMS fields will solve most of your issues.