@olivierp unfortunately I don’t think people will make their project clonable since Mixitup 3 multifilter require a paid licence.
However, I recently did an extensive Mixitup 3 one dimensional filtering research which I published in this post. Feel free to have a look, you’ll get an idea of what I mean by referencing the categories (here refered as “categ”). You can also have a look at the associated codepen where you can have a look at the structure you should be reproducing in Webflow.