Form submit handler to open new window and reload the current page

Question

I have a form embedded in a block in a node; when submitting the form, it has to do two things:

1. Open another new window to a custom route
2. Reload the current page

The first point works correctly, but refreshing the current page is not working. Here is a snippet of the code:

public function buildForm(array $form, FormStateInterface $form_state) {
  $form['actions']['submit'] = [
    '#type' => 'submit',
    '#value' => $this->t('Join'),
  ];

  $form['#attributes'] = ['target' => '_blank']; // Open new window.
}

public function submitForm(array &$form, FormStateInterface $form_state) {
  // Open new window.
  $form_state->setResponse(new TrustedRedirectResponse($url));

  // Reload the current page.
  $request = $this->getRequest();
  $this->redirect($request->getUri());
}

I tried to use onclick="return location.reload();" within the button tag but it fires before submitting the form.

Any ideas?