Fix my php woocommerce code

My code is below please tell me why my out of stock message is not showing up (the in stock message works fine)

dd_action('woocommerce_after_add_to_cart_form', function() {
global $product;
if ( $product->is_in_stock() ){
echo '<i>In stock. Usually delivered in 2 - 3 bus. days</i>';
}else{
if (!$product->is_in_stock()) {
$availability = __('Sold Out: Back in stock late May 2022. Enter your email to be notified', 'woocommerce');
} elseif ($product->managing_stock() && $product->is_on_backorder(1)) {
$availability .= $product->backorders_require_notification() ? __('Available on backorder', 'woocommerce') : '';
} elseif ($product->managing_stock()) {
// $availability = __($free_delivery, 'woocommerce');
$stock_amount = $product->get_stock_quantity();
switch (get_option('woocommerce_stock_format')) {
case 'low_amount':
if ($stock_amount <= get_option('woocommerce_notify_low_stock_amount')) {
/* translators: %s: stock amount */
$availability = sprintf(__('Only %s Available!', 'woocommerce'), wc_format_stock_quantity_for_display($stock_amount, $product));
}
break;
case '':
/* translators: %s: stock amount */
$availability .= sprintf(__('%s Available!', 'woocommerce'), wc_format_stock_quantity_for_display($stock_amount, $product));
break;
}
if ($product->backorders_allowed() && $product->backorders_require_notification()) {
$availability = ' ' . __('(can be backordered)', 'woocommerce');
}
} else {
$availability = '';
}
}
}, 10);