How to display only posts from the last day with posts published?

Question

The goal is to show today's published posts or, if there's none, the last day's with posts published posts.

I found this old question, but the code suggested uses query_posts. I'd like to use WP_Query. I tried to scramble something, but it didn't work:

    $current_year = date('Y');
    $current_month = date('m');
    $current_day=date('d');

    $today = getdate();
    $last_date = $wpdb->get_var("SELECT DATE(MAX(post_date)) FROM {$wpdb->posts} LIMIT 1");
    if (!empty($last_date)) {
    list($current_year,$current_month,$current_day) = explode('-',$last_date);
   } 

    $args = array(
        'date_query' => array(
            array(
                'after'     => array(
                    'year'  => $today["year"],
                    'month' => $today["month"],
                    'day'   => $last_date,
                ),
                'inclusive' => true,
            ),
        ),
        'posts_per_page' => -1,
    );

Any idea what's wrong?