sendAction works with angle brackets

components.my-component\.js

import Component from '@ember/component';
import { action } from "@ember/object";
import { tracked } from "@glimmer/tracking";

export default class extends Component {
  @tracked count = 0;

  @action
  update() {
    this.sendAction("onChange", ++this.count);
  }
}

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from "@glimmer/tracking";
import { action } from "@ember/object";

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
  @tracked updates = 0;
  @action
  changeMe(v) {
    this.updates = v;
  }
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
Updates: {{this.updates}}<br>
<MyComponent @onChange={{this.changeMe}}/>
<br>
{{outlet}}
<br>
<br>

templates.components.my-component\.hbs

<button {{on "click" this.update}}>Update {{this.count}}</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"
  }
}