backend

personal_data:
  '#type': html_tag
  '#tag': h3
  '#value': 'Personal data'

$form['nodes'] = [
    '#title' => $this->t('Select articles'),
    '#type' => 'entity_autocomplete',
    '#target_type' => 'node',
    '#tags' => TRUE,
    '#selection_handler' => 'default',
    '#selection_settings' => ['target_bundles' => ['article']],
    '#default_value' => $default_nodes,
];

$form['nodes'] = [
    '#title' => $this->t('Select articles'),
    '#type' => 'entity_autocomplete',
    '#target_type' => 'node',
    '#maxlength' => 1024,
    '#tags' => TRUE,
    '#selection_handler' => 'default',
    '#selection_settings' => ['target_bundles' => ['article']],
    '#default_value' => $default_nodes,
];

<?php

namespace Drupal\scp_base\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

class RouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  protected function alterRoutes(RouteCollection $collection) {
    // Make sure profile pages are not admin pages, in order to load the right
    // translation.
    if ($route = $collection->get('profile.user_page.single')) {
      $route->setOption('_admin_route', FALSE);
    }
  }

}