When JS is not needed. Actual zero JS. Nextjs and other SSGs all still ship some JS. Astro can ship 0 JS, however working with actual html files allows for much better developer experience and the overall setup is tiny so you can focus on just building.
JDrechsler/Template-Zero-JS
When JS is not needed. Actual zero JS. Nextjs and other SSGs all still ship some JS. Astro requires a whole new tooling.
HTML