How do I change option name?

I have sort link ‘Best’ in exposed form. I want after user click this link, link title changes to ‘New’

I’m try this, but it don’t work:

function helper_form_views_exposed_form_alter(array &$form, FormStateInterface $form_state, $form_id) {
    if($form('#id')== 'views-exposed-form-pozdravleniya-taxonomy-term-page-1') {
      $form('sort_by')('#title') = '';
      $form('sort_by')('#options')('created') = '';
      if ($form('sort_by')('#value') == 'count') {
        $form('sort_by')('#options')('count') = 'New';
      }
    }
}

Also I’m try this, it don’t work too:

function helper_form_views_exposed_form_alter(array &$form, FormStateInterface $form_state, $form_id) {
    if($form('#id')== 'views-exposed-form-pozdravleniya-taxonomy-term-page-1') {
      $form('sort_by')('#title') = '';
      $form('sort_by')('#options')('created') = '';
      if ($form_state->getValue('sort_by') == 'count') {
        $form('sort_by')('#options')('count') = 'New';
      }
    }
}

Screenshot form dump