Add order detail metadata to the checkout email and the admin order page in Woocommerce

We have products that are defined as "Kits". They are products that have a list of other products that constitute a kit. The data defining the kit is stored in an array as metadata. I created a hook that displays the metadata on the product page and in the cart. I need to do something similar for the "completed order email" and the "admin order page" but I can't figure out how to go about doing that. Here is the hook that I created:

add_filter( 'bis_show_kit_meta', 'bis_show_kit_meta_contents', 10, 3 );
function bis_show_kit_meta_contents($productID)
{
    global $wpdb;
    $postMeta = get_post_meta($productID,'',true);
    if ((isset($postMeta['bis_kit_id'])) and ($postMeta['bis_kit_id'][0] > 1)) {
        echo 'This is a Kit containing the following items:<br>';
        echo $postMeta['bis_kit_type'][0].'<br>';
        foreach($postMeta as $kititem) {
            foreach ($kititem as $value) {
                $newvalue = unserialize($value);
                if ($newvalue) {
                    $newvalue2 = unserialize($newvalue);
                    if($newvalue2['type']=="kititem"){
                        echo '<li>' .$newvalue2['quantity']. ' -> ' .chr(9). $newvalue2['name']. '</li>';
                    }
                }
            }
        }
    }
}

The current function is hooked to the respective templates in my child theme.

I can't figure out how to apply a similar function to the customer-completed-email.php file and I have no idea where to hook in the admin edit order pages.

I found some code in another post which looks similar to what I need to do but I can't figure out what file the modifications for the admin order is in.

The code I found is:

add_action('woocommerce_before_order_itemmeta','woocommerce_before_order_itemmeta',10,3);

function woocommerce_before_order_itemmeta($item_id, $item, $product){
   ...
}

Any suggestions would be greatly appreciated.

source https://stackoverflow.com/questions/76900861/add-order-detail-metadata-to-the-checkout-email-and-the-admin-order-page-in-wooc