How do I hide posts in a category from all listings but still allow the posts to be viewed?

Question

Let's say I have a category named "Hidden". I'd like to prevent all posts in "Hidden" from appearing within The Loop on the main blog listing page.

Also, I'd like to prevent those posts from appearing anywhere else (category listing pages, archives, etc.)

However, I'd still like the posts to be accessible via their permalink. Is this possible?

Thanks! :)

Answer 1

Answering my own question here:

Is it really as easy as including this within a pre_get_posts filter?

$query->set('category__not_in', $term_id);