BlockUser.php

<?php

namespace Drupal\user\Plugin\Action;

use Drupal\Core\Action\ActionBase;
use Drupal\Core\Action\Attribute\Action;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;

/**
 * Blocks a user.
 */
class BlockUser extends ActionBase {
    
    /**
     * {@inheritdoc}
     */
    public function execute($account = NULL) {
        // Skip blocking user if they are already blocked.
        if ($account !== FALSE && $account->isActive()) {
            // For efficiency manually save the original account before applying any
            // changes.
            $account->original = clone $account;
            $account->block();
            $account->save();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function access($object, ?AccountInterface $account = NULL, $return_as_object = FALSE) {
        
        /** @var \Drupal\user\UserInterface $object */
        $access = $object->status
            ->access('edit', $account, TRUE)
            ->andIf($object->access('update', $account, TRUE));
        return $return_as_object ? $access : $access->isAllowed();
    }

}