I do loops with custom content shortcode and need to tag up content just like the masonry grid ex.
You’ll have write your shortcode to enqueue script/s for masonry library (usually jquery-masonry) and add the classes + inline scripts used for masonry to this custom shortcode’s printed markup for it to work.
This is pretty tricky to do and is most likely time consuming.
You may be better of using a plugin that already does all of this (WP Show Posts) and set the query to display only posts from the “news” category.