Over engineered. Just write it in pure HTML/CSS. It's a resume, you don't need anything more advanced.
Print to PDF if you need to via the browser, and you're good to go!
I mean I personally would use a static site generator too, but objectively speaking: for a single page (no navigation, not printed page)... It really is overkill
One thing I did that I like was after the most recent jobs, the older and less relevant ones were faded a bit. A hover would make them dark and easier to read. When printing a PDF, only the darker more recent ones would print. This let me keep a full record in a single file (mostly for my own benefit), while still being able to quickly and easily print out a single page version.
You could have structured data as json etc within that html, and some Javascript that renders that onto final html. Than add a button (or a URL argument, or print action) that returns final html (including all your Javascript). That way you only ever need to update your structured data while never needing to edit the html itself. You could theoretically even add some interface to update the resume. I am thinking tiddlywiki but for the CV.
May be that's what you are saying in your comment already. It will be self
That then leads to the idea of having an api endpoint for your resume data, since it's already in json, with an industry standard format. So instead of all these sites parsing a human formatted resume or text file, they could skip the middle man and have structured data to work with. The downside here would be needing to host it somewhere that can deal with server side code. Or maybe this is a startup idea.