Add custom Validation before checkout in address

Hi dears I want to add validation for vat number in shipping or billing addresses when user wants to checkout.
As old I have a validation module who has works well for fields in register page.
Now I want to add my custom validation for tax/vat number (vat_id)
Note: I enabled show vat number on storefront.

I Created a file in setup > UpgradeData.php with Below Code:

namespace VendorModuleSetup;
 
use MagentoEavSetupEavSetup;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupModuleDataSetupInterface;
use MagentoFrameworkSetupUpgradeDataInterface;
 
class UpgradeData implements UpgradeDataInterface
{

    public function __construct(
        MagentoCustomerSetupCustomerSetupFactory $customerSetupFactory
    ) {
        $this->customerSetupFactory = $customerSetupFactory;
    }
 
    /**
     * Upgrades customer_eav_attribute table for validate_rules to set limit on character for first and lastname
     *
     * @param ModuleDataSetupInterface $setup
     * @param ModuleContextInterface $context
     * @return void
     */
    public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        $setup->startSetup();
        /** @var CustomerSetup $customerSetup */
        $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);
 
        $entityAttributes = [
            'customer_address' => [
                'firstname' => [
                    'validate_rules' => '{"max_text_length":213,"min_text_length":2}'
                ],
                'lastname' => [
                    'validate_rules' => '{"max_text_length":255,"min_text_length":2}'
                ],
                'vat_id' => [
                    'validate_rules' => '{"max_text_length":9,"min_text_length":9,"input_validation":"myvalidation"}',
                    'attribute_model' => 'MagentoCustomerModelAttribute',
                    'is_required' => true,
                    'frontend_label' => 'Vat Code',
                    'frontend_input' => 'text',
                    'used_in_forms' => ['adminhtml_customer','adminhtml_checkout','adminhtml_customer_address','customer_address_edit','customer_account_create','customer_account_edit','customer_register_address'],
                ],
            ],
            'customer' => [
                'firstname' => [
                    'validate_rules' => '{"max_text_length":255,"min_text_length":2}'
                ],
                'lastname' => [
                    'validate_rules' => '{"max_text_length":255,"min_text_length":2}'
                ],
            ],
        ];
        $this->upgradeAttributes($entityAttributes, $customerSetup);
        $setup->endSetup();
    }
 
    protected function upgradeAttributes(array $entityAttributes, MagentoCustomerSetupCustomerSetup $customerSetup)
    {
        foreach ($entityAttributes as $entityType => $attributes) {
            foreach ($attributes as $attributeCode => $attributeData) {
                $attribute = $customerSetup->getEavConfig()->getAttribute($entityType, $attributeCode);
                foreach ($attributeData as $key => $value) {
                    $attribute->setData($key, $value);
                }
                $attribute->save();
            }
        }
    }
}

I used above way but when I go for checkout show below error:

Notice: Undefined index: myvalidation in /public_html/vendor/magento/module-checkout/Block/Checkout/AttributeMerger.php on line 174