Nested Tree with One Component

components.render-node\.js

import Component from '@glimmer/component';

export default class extends Component {
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  tree = {
    id: 1,
    children: [
      {
        id: 2,
        children: [
          {
            id: 3
          }
        ]
      },
      {
        id: 4
      },
      {
        id: 5,
        children: [
          { id: 6 },
          { id: 7, children: [{ id: 8 }] }
        ]
      }
    ]
  }
}

helpers.get-element-by-id\.js

import { helper } from '@ember/component/helper';

export default helper(function getElementById([id]) {
  return document.getElementById(id);
});

templates.application\.hbs

<RenderNode 
  @node={{this.tree}} 
  style="border: 1px solid black; padding: 10px;" as |node|
>
  <h1>{{node.id}}</h1>
</RenderNode>

templates.components.render-node\.hbs

<div ...attributes id={{@node.id}}>
  {{yield @node}}

  {{#if @node.children}}
    {{#each @node.children as |childNode|}}
      {{!-- While we can't actually render each yielded element in a 
            tree-like structure, we _can_ force the DOM nodes to be nested
            using the `in-element` helper --}}
      {{#-in-element (get-element-by-id @node.id)}}
      	<RenderNode @node={{childNode}} ...attributes as |child|>
          {{yield child}}
        </RenderNode>
      {{/-in-element}}
    {{/each}}
  {{/if}}
</div>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}