Hugo is pretty agnostic for the content but is a pain to use imo. I'm working on Zola (https://www.getzola.org/) in order to have something simpler. It doesn't have all the features (eg multiple language sites) of Hugo yet but it's getting there. Working for things other than blog was very important, so you can implement something like gitbook in 3 small templates: https://zola-book.netlify.com/chapter1/ (source at https://github.com/getzola/book).