在深入研究源代码之后，最终得到了这个解决方案。对我有用，也可能对其他人有用。

function get_rest_items_query($post_type, $posts_per_page, $orderby = \'date\', $order = \'desc\') {

    $result = array();
    $args = array( \'post_type\' => $post_type, \'posts_per_page\' => $posts_per_page, \'orderby\' => $orderby, \'order\' => $order );
    $posts = get_posts($args);

    $ids = implode(\',\', wp_list_pluck($posts, \'ID\'));

    // request
    $restRequest = new WP_REST_Request(\'GET\', \'/wp/v2/\' . $post_type  );
    $restRequest->set_param(\'include\', $ids);
    // response
    $response = rest_do_request( $restRequest );
    // _embed
    $rest = rest_get_server()->response_to_data( $response, true );

    $result[\'posts\'] = $rest;

    return $result;
}