Hiding a category from public

Hello there and thanks for reading this.
I tried the search option but I keep ending up in topics with very difficult sollutions to a problem im not even sure is the same as mine.

I would like to create 1 category that is only visable to “moderators/admins” of this specific site.
All I can come up with is keeping the posts as a draft instead of publishing them, but then the category we called “admin-only” will always be visable never showing any topic. I would rather just make this category not visable online @ all. (but still able to use uploaded files)

I hope there is a sollution to my problem.

Thanks on forehand