Just to share this:
There are no options to filter Articles. Only Portfolios.
All news have been edited in Articles since a comple of years. And they have now been assigned complex Categories / sub-categories we would like to use. So I still needed to filter Articles, not Portfolios.
So I finally used Classic Tabs, each of one containing specific Category container. I copied the code found in the page in Wordpress edition mode into the fields as follows:
[x_recent_posts type=“post” count=“4” offset="" category=“the-one-I-want” orientation=“horizontal” no_sticky=“true” no_image=“false” fade=“false”]