$conn = mysqli_connect('localhost', 'root', 'qwerty', 'rodzinny-zakatek');

if ($conn && isset($_GET['add-posts'])) {
    for ($i=0; $i < 24; $i++) {

        $args = array(
            'post_type' => 'lokale',
            'post_status' => 'publish',
            'post_title' => 'Etap VI nr.' . ($i+1),
            //'post_category' => array(23),
            'meta_input' => array(
                'status' => 'inaccessible',
                'stage' => 'stage6',
                'area' => '86',
                'return' => 'IV kwartał 2020',
                //'local-price' => '315000'
            ),
        );

        $postID = wp_insert_post($args);

        $sql = "INSERT INTO mwp_term_relationships (object_id,term_taxonomy_id, term_order) VALUES ( $postID, 28, 0 )";

        $conn->query($sql);

    }
}

$conn->close();