OptionsTestHooks.php

<?php

declare (strict_types=1);
namespace Drupal\options_test\Hook;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Hook\Attribute\Hook;

/**
 * Hook implementations for options_test.
 */
class OptionsTestHooks {
    
    /**
     * Implements hook_form_FORM_ID_alter().
     */
    public function formEntityTestEntityTestFormAlter(&$form, FormStateInterface $form_state, $form_id) : void {
        if (\Drupal::state()->get('options_test.form_alter_enable', FALSE)) {
            $form['card_1']['widget']['#required_error'] = t('This is custom message for required field.');
        }
    }
    
    /**
     * Implements hook_options_list_alter().
     */
    public function optionsListAlter(array &$options, array $context) {
        if ($context['fieldDefinition']->getName() === 'card_4' && $context['widget']->getPluginId() === 'options_select') {
            // Rename _none option.
            $options['_none'] = '- Select something -';
        }
        if ($context['fieldDefinition']->getName() === 'card_4' && $context['entity']->bundle() === 'entity_test') {
            // Remove 0 option.
            unset($options[0]);
        }
    }

}