Custom fields order (wordpress)

Order by first and last name from custom fields.

<?php
  $q = new WP_Query([
    'category_name' => 'orders',
    'meta_query' => [
      'ln' => [
        'key' => 'ln',
      ],
      'fn' => [
        'key' => 'fn',
      ],
    ],
    'orderby' => [
       'ln' => 'ASC',
       'fn' => 'ASC',
    ],
    'posts_per_page' => -1,
  ]);
  if ($q->have_posts()) {
    echo '<ul>';
    while ($q->have_posts()) {
      $q->the_post();
      $fn = get_post_meta(get_the_ID(), 'fn', true);
      $ln = get_post_meta(get_the_ID(), 'ln', true);
      printf(
        '<li><a href="%s">FN: %s LN: %s</a></li>',
        esc_url(get_permalink()),
        esc_html($fn),
        esc_html($ln),
      );
    }
    echo '</ul>';
  }
  wp_reset_postdata();
?>

template.php

< toolbox