I am trying to add an include a template file located in my active child theme:
childtheme/woocommerce/myaccount/order-a-kit.php 
The function use also echo "Hello World" which is displayed successfully, but not the included php template file.
I have tried those:
include($_SERVER['DOCUMENT_ROOT']."twentyseventeen-child/woocommerce/myaccount/order-a-kit.php");
include($get_stylesheet_directory_uri()."twentyseventeen-child/woocommerce/myaccount/order-a-kit.php");
include 'twentyseventeen-child/woocommerce/myaccount/order-a-kit.php';
The content of the order-a-kit.php is super simple, I am just trying to include that file: 
<?php
?>
<div>
    <p>
        Look at me
    </p>
</div>
This is my function.php section and everything is doing as it should except the include function towards the bottom:
add_filter( 'woocommerce_account_menu_items', 'add_my_menu_items', 99, 1 );
function add_my_menu_items( $items ) {
    $my_items = array(
    //  endpoint   => label
        'order-a-kit' => __( 'Order A Kit', 'woocommerce'),
        'orders' => __( 'Order History', 'my_plugin' ),
    );
    $my_items = array_slice( $items, 0, 1, true ) +
        $my_items +
        array_slice( $items, 1, count( $items ), true );
    return $my_items;
}
//adding custom endpoint 
function my_custom_endpoints() {
    add_rewrite_endpoint( 'order-a-kit', EP_ROOT | EP_PAGES );
}
add_action( 'init', 'my_custom_endpoints' );
function my_custom_query_vars( $vars ) {
    $vars[] = 'order-a-kit';
    return $vars;
}
add_filter( 'query_vars', 'my_custom_query_vars', 0 );
function my_custom_flush_rewrite_rules() {
    flush_rewrite_rules();
}
add_action( 'wp_loaded', 'my_custom_flush_rewrite_rules' );
//including custom endpoint
function my_custom_endpoint_content() {
    include 'twentyseventeen-child/woocommerce/myaccount/order-a-kit.php';
    echo '<p>Hello World!</p>';
}
add_action( 'woocommerce_account_order-a-kit_endpoint', 'my_custom_endpoint_content' );
?>
Any help is greatly appreciated.
 
     
     
    