Expose method creating a web-component using Vue3

I am creating a web-component using VueJS 3, I want to expose a method on the component allowing the user to do something like this:

  <custom-component id="x1" />

  <script>
    var component = document.getElementById("x1");
    
    component.customMethod(); // as focus() method on native elements
  </script>

If I define a method on the component, I can call the method inside the component. But the method is not available when I use it as a web-component.

  //main.ts/js
  import { defineCustomElement } from "vue"
  import component from "./component.ce.vue"

  const element = defineCustomElement(component );

  customElements.define("custom-component ", element);

  //component.ce.vue
  const customMethod = () => { console.log("Exected"); }

How I can indicate to Vue Component Wrapper that the customMethod will be available outside the component?