Can I add an option to an existing option set via workflow?

I am trying to create a workflow where users select a “Category” from a drop down. The drop down is populated by an option set “Categories” and originally shows all options. If the “Category” doesn’t exist the user can add that category to the existing option set “Categories”. Is this possible and if so, how do I do this?

Option sets are non-mutable.

You must turn your categories into a dynamic data-set.

You can “merge” your option sets to get both the Static & Dynamic categories, but that will take a little more “know-how”.

That’s what I originally thought. Researched through perplexity and it gave specific instructions as to how to do this but those obviously weren’t correct. Thanks for your help!