Get single post from tags array

$args = array(
'type' => 'post',
'orderby' => 'name'
);
$tags = get_tags($args);
foreach($tags as $tag) {
$the_query = new WP_Query( 'tag='.$tag->name );
if ( $the_query->have_posts() ) {
$the_query->the_post();
$desired_posts[] = get_the_ID(); // all the post IDs stored here.
} else {
// no posts found
}
wp_reset_postdata();
}
$args1 = array(
'post_type' => 'post',
'orderby' => 'date',
'post__in' => $desired_posts,
'posts_per_page' => -1
);
$the_query = new WP_Query( $args1 );
echo '<ul>';
if ( $the_query->have_posts() ) {
while ( $the_query->have_posts() ) {
$the_query->the_post();
echo '<li>'. get_the_title() . '</li>';
}
} else {
// no posts found
}
echo '</ul>';