Remove the categories prefix on plugin removal

Hi! Up until recently, I used the Yoast plugin with ‘Remove the categories prefix’ set to ‘Yes’.

Now that I deactivated the plugin, my category pages have the /category/ prefix all of a sudden. And I want to remove the /category/ prefix so the URL of the category doesn’t look different to Google.

So I’ve tried adding this function:

function remove_category( $string, $type )  {           if ( $type != 'single' && $type == 'category' && ( strpos( $string, 'category' ) !== false ) )          {              $url_without_category = str_replace( "/category/", "/", $string );              return trailingslashit( $url_without_category );          }      return $string;  }     add_filter( 'user_trailingslashit', 'remove_category', 100, 2);  

to my functions.php in my child theme but it isn’t working. Is there something that Yoast leaves behind that stops this function from working?

Thanks!