displaying taxonomy term as a header in a view
You should probably try to create a Taxonomy term View and not a Content View. Then, you could add a relationship (Taxonomy term : content with term) to fetch your node fields (or rendered entities). Add a taxonomy term filter to select your certain taxonomy term. Add a sort criteria based on descending post date (relationship with content). Display only 3 items. Finally, the taxonomy term name will become your View title and I guess you're done.