code: protected function getTaxonomies(string $post_type): array
      {
          $return = [];
  
          $taxes = \get_object_taxonomies($post_type, 'objects');
  
          foreach ($taxes as $tax_slug => $tax_object) {
              if (\is_taxonomy_hierarchical($tax_slug)) {
                  $return[] = $tax_slug;
              }
          }
  
          return $return;
      }
docs: Get all hierarchical taxonomies