Display attributes in order overview

Hi,

I’m trying to add some custom columns to the order overview page.
I have a solution to display anything I want as a new column.
It just won’t work for a product attribute and I can’t seem to fine how it’s stored in the database to retrieve the value.

First I create the column

/* CREATE COLUMN SIZE IN ADMIN WOOCOMMERCE ORDERS */
add_filter( 'manage_edit-shop_order_columns', 'custom_order_cols' );
function custom_order_cols( $columns ) {
	$new_columns = ( is_array( $columns ) ) ? $columns : array();
  	unset( $new_columns[ 'order_actions' ] );
	
  	$new_columns['SIZE'] = 'Size';
	
  	return $new_columns;
}

Next, populate the column

/* POPULATE COLUMN SIZE IN ADMIN WOOCOMMERCE ORDERS */
add_action( 'manage_shop_order_posts_custom_column', 'populate_custom_order_cols', 2 );
function populate_custom_order_cols( $column ) {
	global $post;
	
	$data = get_post_custom_values( 'pa_maat' );

	if ( $column == 'SIZE' ) {
	      foreach ( $size_value as $key => $value ) {
            echo "$value"; 
          }
	}
}

I can use ‘get_post_custom_values’ to get any value I want from the order. Looking at the database, I can retrieve all values I want, except for the product attribute.
I just can’t seem to find this value. Tried ‘get_the_terms’ and other…

Is this even possible?

Thanks and kind regards!