Upon further inspection, I think the biggest difference is that Markdoc uses Nextjs which means you can write React right in the middle of your code and import

Upon further inspection, I think the biggest difference is that Markdoc uses Nextjs which means you can write React right in the middle of your code and import React components. But then again, you have Gatsby that's also based on React and is built for static site generation, and supports Markdown.