WordPress search WP_Query to cover multiple post types and their custom fields?

Question

Found a way to combine WP_Query posts:

$query1 = new WP_Query($args);
$query2 = new WP_Query($args2);
$query3 = new WP_Query($args3);

$combined = new WP_Query();

$combined->posts =   array_merge(
                           $query1->posts
                          ,$query2->posts
                          ,$query3->posts
                        );

Still not as elegant as doing one WP_Query with all those conditions in args being an OR … as in the query should match ANY of those meta_query options.

Also, somewhow array_unique() wrapper to the array_merge() throws an error.