Filter custom post type admin list by custom meta column, where the column is another custom posts meta value

One solution may be to get all position ids, where project id matches and compare them with the ‘OR’ comparer.

$position_ids = get_positions_in_project($project_id);

foreach ($position_ids as $id) {
    $meta_query[] = array(
        'key' => 'feedback_position_relation',
        'value' => $id,
        'compare' => '=',
    );
}

$meta_query['relation'] = 'OR';
$query->set('meta_query', $meta_query)

But the problem with this is, that meta query does not accept complex parameters. I want a feedback where the position id is 1 and project id is 2. The relation will always be ‘OR’.

In a simple problem this solution should give the answer. For my sake this solution does not work, since i want to give the user the ability to filter other parameters too.

I have searched for ‘in array’ meta_query, but this seems to be not supported.

UPDATE

With wordpress 5.8.1 (I have no idea if earlier versions work), the IN Array comparison works.

if ($_GET['project'] != 'all') {
        $project_id = $_GET['project'];
        $positions = get_position_ids_by_project($project_id);
        $meta_query[] = array(
            'key' => 'summary_summary_position',
            'value' => $positions,
            'compare' => 'IN',
        );
    }
$query->set('meta_query', $meta_query)