Making custom column sortable in WooCommerce admin order list

Question

I have my custom column showing data, but I just can't seem to get it to sort. At the moment, if I press the column title for sorting, it only sorts by the date of the orders, rather than the data from this new column. I am especially stuck on what the "value" should be in the array for "meta_query" – everything I have tried hasn't worked. Any help would be much appreciated!

// ----- add column to orders that shows the booking date -----
function ec_order_items_column2($columns) {
    $new_columns = array();
    foreach($columns as $key=>$column){
        $new_columns[$key] = $columns[$key];
        if($key === 'ordered_products') {
            $new_columns['start_date'] = __('Booking Time','woo-custom-ec2');
        }
    }
    return $new_columns;

}
add_filter('manage_edit-shop_order_columns', 'ec_order_items_column2', 99 );




function ec_order_items_column_cnt2($column) {
    global $post, $the_order;
    
    $order_id = $the_order->get_id();
    
    // Replace 'my_custom_column_key' with your desired column key
    if ( 'start_date' === $column ) {
        $display = array();
        
        // Loop through order items
        foreach ( $the_order->get_items() as $item_id => $item ) {
            // $item_id is the current Item ID

            // Get the WC_Product Object
            $product = $item->get_product();
            
            // Get custom order item meta data 
            $meta_value = $item->get_meta('phive_display_time_from');
            
            $display[$item_id] = $meta_value;
            
        }
        // Testing output
        echo implode(' | ', $meta_value);
    }
}

add_action('manage_shop_order_posts_custom_column', 'ec_order_items_column_cnt2', 99);



// ---- make sortable column ----

add_filter( 'manage_edit-shop_order_sortable_columns', 'custom_woo_admin_sort' );
function custom_woo_admin_sort( $columns )
{
    $custom = array(
        'start_date'    => '_phive_display_time_from',
    );
    return wp_parse_args( $custom, $columns );
}



add_action('pre_get_posts', 'custom_booking_orderby');
function custom_booking_orderby( $query ) {
    if ( !is_admin() ){ return; }

    $orderby = $query->get( 'orderby');
    if ('phive_display_time_from' == $orderby){
      $query->set('meta_key','phive_display_time_from');
      $query->set( 'orderby', 'meta_value' );
      $query->set( 'meta_query', array(
        array(
              'key' => 'phive_display_time_from',
              'value' => 'meta_value',
        )
  ));
    }
}