New Twiddle

controllers.application\.js

import Controller from '@ember/controller';
import { action } from "@ember/object";
import { set } from "@ember/object";

export default class ApplicationController extends Controller {
  
	@action
	changeToBim(){
  	set(this.model, "someText", "bim");
  };
  
}

routes.application\.js

import Route from '@ember/routing/route';
import { tracked } from "@glimmer/tracking";

export default class someRoute extends Route {
  model(){
  	return { someText: "boom" }
  }
};

// import Route from '@ember/routing/route';
// import { tracked } from "@glimmer/tracking";

// class TrackedText {
// 	@tracked value;
// }

// export default class someRoute extends Route {  
//   model(){
//     let someText = new TrackedText();
//     someText.value = "boom";
//     console.log("someText", someText);
//   	return { someText }
//   }
// };

templates.application\.hbs

someText: {{this.model.someText}}
<br><br>
<button {{on "click" this.changeToBim}}>Change to "Bim"</button>

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"
  }
}