Next.js is an all-encompassing framework, so your existing static site would need to be placed in its `public` directory. Even then, the React-based frontend wi

Next.js is an all-encompassing framework, so your existing static site would need to be placed in its `public` directory. Even then, the React-based frontend will take dominance. For your use case I'd recommend a command-line tool that converts Markdown files from a given folder and outputs it to a corner of your existing site. There are implementations in various languages, so you can choose according to preference.