Drupal 8 Dynamic field cardinality

example.php

    $field_updated = &$form['YOUR_FIELD_NAME'];
    $field_state = \Drupal\Core\Field\WidgetBase::getWidgetState($form['#parents'], $field_updated['widget']['#field_name'], $form_state);
    // You can change number of item to control the number of items we can change it with another field value into $form_state.
    if ($field_state['items_count'] >= 2) {
      $field_updated['widget']['add_more']['#access'] = FALSE;
    }
    $form['YOUR_FIELD_NAME'] = $field_updated;