German transliteration for IDs in Drupal 9

indëx.php

<?php

// $vars['id'] = GermanHtml::getUniqueId('Öktöberfest');
// → <h1 id="oekoeberfest">Öktöberfest</h1>

class GermanHtml extends Drupal\Component\Utility\Html {
  public static function getId($id) {
    $id = str_replace([
      ' ',
      '_',
      '[',
      ']',
      'ä',
      'ö',
      'ü',
      'ß',
    ], [
      '-',
      '-',
      '-',
      '',
      'ae',
      'oe',
      'ue',
      'ss',
    ], mb_strtolower($id));
    $id = preg_replace('/[^a-z0-9\\-_]/', '', $id);
    $id = preg_replace('/\\-+/', '-', $id);

    return $id;
  }
}