XML动态变化

I have a problem with my XML sitemap. I want insert frequency and priority dynamically, but I don't understand the action register_sitemap

This is my code:

function insert_xml($content){
   global $post;
   $xml_relationship = get_field('c_page_relationship', $post->ID);
   function my_custom_post_freq($default, $url, $post_id) {
      return 'hourly';
   }
   add_filter('wpseo_sitemap_post_single_change_freq', 'my_custom_post_freq', 10, 3);

   function my_custom_post_xml_priority($default, $url, $post_id) {
      return 0.6;
   }
   add_filter('wpseo_xml_sitemap_post_priority', 'my_custom_post_xml_priority', 10, 3);

   return $xml_relationship;
}

add_action('wpseo_do_sitemap_', 'insert_xml');

I am using acf custom fields, to change the prority and frequency which I get from $post_id, the functions about this are not ready, but is the finality. I want to insert when the XML is created for yoast, I find this in the API docs yoast wpseo_do_sitemap_<$type> but i dont understand what is <$type>

$type can not be a valid post type or taxonomy, when they are this action will not trigger

What does it need to be?