django-treebeard: build navbar with nested elements

[jkandrashina]

Hello.
I am using django-treebeard to build a tree-like navbar. Some top level elements of the navbar will have nested elements.

I followed advices from this post to get a working example of the navbar:
Django template nested loop

# models.py

class BaseNav(MP_Node):
    name = models.CharField(max_length=100)
    url = models.CharField(max_length=100)
    position = models.PositiveIntegerField(default=1)
    node_order_by = ['position']
    
    class Meta:
        abstract = True
    
    def __str__(self):
        return self.name


class HeaderNav(BaseNav):
    class Meta:
        verbose_name='Header Navbar'
        verbose_name_plural='Header Navbar'

An inclusion tag of navbar:
# app/templatetags/navigation_tags.py

@register.inclusion_tag('app/blocks/header-navbar.html', takes_context=True)
def show_header_navbar(context):
    root = HeaderNav.get_first_root_node()
    return {'root': root}

Templates:

# header-navbar.html (parent template)

<ul class="navbar-nav">
  {% include 'app/blocks/header-navbar-items.html' with node=root only %}
</ul>

# header-navbar-items.html (child template)

{% if node.is_leaf %}
<li class="nav-item px-4">
  <a class="nav-link" href="{{ node.url }}">{{ node.name }}</a>
</li>
{% else %}
<li class="nav-item dropdown px-4">
  <a href="#" class="nav-link dropdown-toggle" id="navbarDarkDropdownMenuLink" role="button" data-bs-toggle="dropdown" aria-expanded="false">
    {{ node.name }}
  </a>
  <ul class="dropdown-menu" aria-labelledby="navbarDropdown">
  {% for child in node.get_children %}
    {% include 'app/blocks/header-navbar-items.html' with node=child only %}
  {% endfor %}
  </ul>
</li>
{% endif %}

And the structure of the navbar from admin:

Everithing worked well and I got this as a result:

The problem is: I don’t want the root node to be shown on the page. What I really need is root’s children and descendants (shown below).

Any help on this would be appreciated.