Roles and permissions

I was trying to give a user the ability to act as a course creator within a given category, and only within that category. I had imagined two ways of doing this. One was to make a course creator role and apply it to the user in a site context and make a blocking role and apply it to the user in the contexts of all the categories except the one that the user is intended to be a course creator of. This method, however, is not scalable.

As such, I went with the second option, which was to assign the role of course creator directly within the context of the one category. Counterintuitively, this did not work. When I tried logging in as the recipient user through the admin account, there was no evidence that anything had changed. I was also unable to see the hidden courses within the category. When I logged directly in with the recipient account, I could see the hidden courses, I could assign roles under course creator; however, I could not create any courses.

As such, I was wondering if there was a specific way of creating a course creator specific to a category.