TW,
If you look at the current working usage of the term 'Static Site Generator' - especially in the new Jamstack context - you'll see that having javascript in html is presumed. So they are plain html, but with many scripts and connections to 'microservices' and API calls, etc. So not the original usage of 'static' but still superfast and if javascript is turned off most of the content is still there. And they *can* still be non-javascript, depending.
Any way, I think I would be happy with a wiki with a sidebar menu that collapses/expands and comments that somehow save to each tiddler. I have this working inside my own local wiki, just have not been able to get it running on my VPS web server. The workflow will not conform to my usual SSG > Github > Netlify workflow for my 11ty sites. At least I haven't figured out how to do it yet.