POSTCODE make it “optional” on Checkout Block | WordPress.org

/** Other billing fields 
* true = required
* false = optional
*/
add_filter( 'woocommerce_default_address_fields', 'customize_extra_fields', 1000, 1 );
function customize_extra_fields( $address_fields ) {
$address_fields['postcode']['required'] = false; //Postcode
return $address_fields;
}