When email sent via drush, render context is empty

It seems a real major issue for those who sending email messages using queue_mail.
It seems a well-known issue as per this link: https://www.drupal.org/project/drupal/issues/3085157 →

We've tried the renderRoot() but there is no luck, still fails.
We are using queue_mail module with this HTMLMail, so we had to come up with a workaround to execute the queue temporarily in a cronjob calling the browser URL from a controller to overcome this issue.

$queueFactory = \Drupal::service('queue');
$queueManager = \Drupal::service('plugin.manager.queue_worker');
/** @var \Drupal\queue_mail\Plugin\QueueWorker\SendMailQueueWorker $queueWorker */
$queueWorker = $queueManager->createInstance('queue_mail');
/** @var \Drupal\Core\Queue\DatabaseQueue $queue */
$queue = $queueFactory->get('queue_mail');
if ($queue->numberOfItems() > 0) {
  // Get the number of items to process
  for ($i = 0; $i < $queue->numberOfItems(); $i++) {
    // Process the queue
    if ($item = $queue->claimItem()) {
      $workerResponse = $queueWorker->processItem($item->data);
      if (!empty($workerResponse) && !empty($workerResponse['result']) && ($workerResponse['result'] === TRUE)) {
        $queue->deleteItem($item);
      }
      else {
        // We will release it immediately.
        $queue->releaseItem($item);
      }
    }
  }
}

CAUTION: This should be used only in cases where there are not too many emails, this is not a scalable solution and should be used only for small/experimental sites.