List All Custom Taxonomy With Child

I have been at this for hours and can’t figure out how to do this.

Here is what I am trying to achieve:

https://www.reed.co.uk/courses/

As you can see it looks like a parent – child relationship between the categories with an icon prepended to the parent category.

I basically want the parent category along with an icon prepended and list it’s children.

I’ve been trying and deleting code for hours, i’v read through get_categories and get_terms but still not figuring out how to do this.

For the icon that’s the least of my worries, I might just use a switch statement to assign an icon based on the category name (these categories are unlikely to be changed)

$parent = get_terms( 'course');
  //  $parent = get_category_parents( $cat_parent, true, ' » ' );

  foreach( $parent as $cat_parent ){

    echo '<div class="courses-container" style="float: left; border: 1px solid;">';
   echo '<h2><a href="' . get_term_link( $cat_parent ) . '">'.$cat_parent->name.'</a></h2>';

    $term_id = $cat_parent->term_id;
    $taxonomy_name = 'course';
    $termchildren = get_term_children( $term_id, $taxonomy_name );

    echo '<ul class="course-child">';
    foreach ( $termchildren as $child ) {
      $term = get_term_by( 'id', $child, $taxonomy_name );
      echo '<li><a href="' . get_term_link( $child ) . '">' . $term->name . '</a></li>';
    }
    echo '</ul>';

    echo '</div>';
  }

The children categories are working perfectly and listing. But I am having some issues when I assign a course to more than one category whether parent or child. The page is populating with every category I assign I assign that post to, I just want all the parent categories and children listed below them. I know I’m close but I can’t figure it out