davidduckwitz

I’ve found Solution by myself.
Here’s what i’ve done, maybe it can help other Developers, too:

1. Define you date when post should be expire (in my case now +28 days):

$date = new DateTime('now +28 days');
$expires = date_format($date, 'Y-m-d H:i:s');

2. Create Post with wp_insert_post and get post ID

// Build Post Array
$my_post  = array(
	'post_author' => wp_strip_all_tags($user_id),
	'post_category' => array( $cat ),
	'post_content' => $postContent,
	'post_content_filtered' => '',
        'post_title' => $value->name,
	'post_excerpt' => '',
		'post_status' => 'publish',
		'post_type' => 'post'			
	);
			
      // Insert the post into the database and get ID
	$post_id = wp_insert_post( $my_post );

3. Add Post Metas for eypiration (delete Posts if expired)

//create Post Meta (In this Case it's the expiration date for postexpire)
				
$ts = get_gmt_from_date("$expires",'U');
update_post_meta($post_id, '_expiration-date', $ts);
			
$opts['expireType'] = "delete";
$opts['id'] = $post_id;			
update_post_meta($post_id, '_expiration-date-options', $opts);
			
update_post_meta($post_id, '_expiration-date-status','saved');

Best Regards from Germany