I figured out that the css preprocessor is not really a thread.
I was using this great tool: https://www.npmjs.com/package/s2sconvert
Now my build can handle both SASS and Stylus
Unfortunately Quasar wont be our choice as it turned out that it is a kind of fullstack spa, and i need a very specific own made build, vue-cli is not an option for us.
But you did a great work, I wish you much success!