Hugo isn’t a server, per se. It’s basically just a template engine. It was originally focused on turning markdown into web pages, with some extra functionality around generating indexes and cross-references that are really what set it apart from just a simple rendering engine. And by now, much of its value is in the huge number of site templates built for Hugo. But what Hugo does is takes some metadata, whatever markdown content you have, and it generates a static web site. You still need a web server pointed at the generated content. You run Hugo on demand to regenerate the site whenever there’s new content (although, there is a “watch” mode, where it’ll watch for changes and regenerate the site in response). It’s a little fancier than that; it doesn’t regenerate content that hasn’t changed. You can have it create whatever output format you want - mine generates both HTML and gmi (Gemini) sites from the same markdown. But that’s it: at its core, it’s a static site template rendering engine.

It is absolutely suitable for creating a portfolio site. Many of the templates are indeed such. And it’s not hard to make your own templates, if you know the front-end technologies.