Custom tag template to list posts in ASC order

Instead of creating a new query, consider reusing the existing global query:

<?php if ( have_posts() ) : ?>
    <?php while ( have_posts() ) : the_post(); ?>           
                    
        <div class="container">

Then, to adjust the order, adjust the global query object by hooking into the pre_get_posts hook:

/**
 * Alters the tag archive query to sort ascending.
 *
 * @param WP_Query $query The WP_Query instance (passed by reference).
 */
function _alter_tag_archive_query( $query ) {
  if ( ! $query->is_admin && $query->is_main_query() && $query->is_tag() ) {
    $query->set( 'order', 'asc' );
  }
}
add_action( 'pre_get_posts', '_alter_tag_archive_query' );