Thank you for the response, but this is my problem:
– I want to hide the archive category from the forum index, not from the entire website. My archive page contains the shortcode: [bbp-single-forum id=488], which is the id of the category.
Participants should be able to go to the archive. I want an archive category to save old discussions, but I don’t want the archive category and its subforums to show up in the forum index, as this is too messy.