Woocommerce email notification for pending order status after 10 minutes

functions.php

add_filter( 'woocommerce_new_order_email_allows_resend', '__return_true' );

add_action( 'woocommerce_checkout_order_processed', 'pending_new_order_notification', 20, 1 );

function pending_new_order_notification( $order_id ) {
	$delayTime = 600;

    as_schedule_single_action(time() + $delayTime, 'queue_pending_email', array( $order_id ), 'customActions');
}

add_action( 'queue_pending_email', function( $order_id ) {
    // Thank you to @LoicTheAztec for this section of code

    $order = wc_get_order( $order_id );

    // Only for "pending" order status
    if( ! $order->has_status( 'pending' ) ) return;
    
    // Get an instance of the WC_Email_New_Order object
    $wc_email = WC()->mailer()->get_emails()['WC_Email_New_Order'];

    ## -- Customizing Heading, subject, additional content (and optionally add recipients)  -- ##
    // Change Subject
    $wc_email->settings['subject'] = __('{site_title} - New customer pending order ({order_number}) - {order_date}');

    // Change Heading
    $wc_email->settings['heading'] = __('New Order Still Pending'); 
    // $wc_email->settings['recipient'] .= ',[email protected]'; // Add email recipients (coma separated)

	// Change additional content
    $wc_email->settings['additional_content'] = __('This order is currently pending.');

    // Send "New Email" notification (to admin)
    $wc_email->trigger( $order_id );
}, 20, 1 );

This gist uses action scheduler to send an email if an order is still pending after 10 minutes. Helpful for receive a notification for when an order is stuck in "Pending Payment"