WP_safe_redirect not working

Instead of the project archives in my Divi theme being at /project_category/[category name]/ I want them to go to /portfolios/#[category name].

I modified the following code from this question and added it to my child theme’s functions.php file.

However this is not working. The project categories are still going to /project_category/[category name]/. I can’t tell if the my_category_redirect function is even being called.

Any help is much appreciated!