Best practice: Many hierarchical vs. few non-hierarchical taxonomies

I’m building a site that will eventually host thousands of posts, all from the same custom post type “Artwork”.

Each blog post has multiple custom taxonomy terms assigned, e.g. “Artist”, “Project”, “Artdirector”, “Format” and more.

I have read that too many taxonomies and/or terms can slow down the page. So I’m not sure if I should build a structure with many non-hierarchical taxonomies, or with only one or two hierarchical taxonomies but more terms and child-terms.

Many taxonomies, mostly non-hierarchical:


Fewer Taxonomies, but hierarchical:

Is there an advantage/disadvantage of any of these two structures when it comes to speed of the website? My concern is that it could become slow once 1000s of posts are on the page.