Render "Page Manager" page programmatically in controller

$page = Page::load('page_name');
if ($page) {
 $variants = $page->getVariants();
 $pageVariant = end($variants);
 if ($pageVariant) {
   $viewer = new PageVariantViewBuilder();
   if ($viewer) {
     return $viewer->view($pageVariant);
   }
 }
}