Check the “bin” Direktory, there you can find “watch/build-administration/Storefront” you maybe need to chmod +x those files.
Its possible to ein shopware6 without node-js in production Server but then you need to build your Storefront and Administration in a dev-enviroment with node. When you build without node the previous built js&scss files are copied and merged from those bash scripts which i mentoined above.