Drupal 8 get page title from route and set this to page_title block

hook.theme.php

function HOOK_preprocess_block__page_title_block(&$variables) {
  $request = \Drupal::request();
  $route_match = \Drupal::routeMatch();
  $page_title = \Drupal::service('title_resolver')->getTitle($request, $route_match->getRouteObject());
  if (!empty($page_title) && empty($variables['content']['#title'])) {
    $variables['content']['#title'] = $page_title;
  }
}