New Twiddle

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from '@glimmer/tracking';
export default class ApplicationController extends Controller {
  queryParams = ['projects', 'roles'];
  @tracked projects = [];
	@tracked roles = [];

}

templates.application\.hbs

<LinkTo @route="application" @query={{hash projects=(array 1 2 3)}}>1.) click me [app with query params]</LinkTo>
<br>
<LinkTo @route="application">2.) click me [no query params]</LinkTo>

{{log this.projects}}

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"
  }
}