GoogleFont in LitElement ShadowDOM

Question

I'm creating a component in LitELement, with ShadowDOM, where I want to display an icon from GoogleFonts' Material Symbols Outlined.

In index.html, I am using this url:

https://fonts.googleapis.com/css2?family=Material+Symbols+Outline

as a regular css link:

<link href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined" rel="stylesheet"/>

And it works fine when I drop something like

<span class="material-symbols-outlined">
  search
</span>

directly in index.html. But when I move it into the ShadowDOM component, it doesn't work. So, assuming that the index.html <link> has to stay in index.html in order to provide @font-face, I've tried to inject the stylesheet into the ShadowDOM to provide the class declaration (.material-symbols-outlined) - in three ways:

1. Via css import:

   @customElement('my-comp')
   export class MyComponent extends LitElement {
     static styles = [
       css`
         @import url("https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined");
       `
     ];
   
     render() {
       return html`
         <span class="material-symbols-outlined">search</span>
       `;
     }
   }
   

2. Via link in render:

   @customElement('my-comp')
   export class MyComponent extends LitElement {
     render() {
       const iconsCssLink = html`
         <link href="https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined" rel="stylesheet"/>
       `;
   
       return html`
         ${iconsCssLink}
         <span class="material-symbols-outlined">search</span>
       `;
     }
   }
   

3. Via a shared component containing styles only:

    @customElement('icon-styles')
    export class IconStylesComponent extends LitElement {
      static styles = [
        css`
          @import url("https://fonts.googleapis.com/css2?family=Material+Symbols+Outlined");
        `
      ];
    }
   

   and then importing it into the target component with ShadowDOM:

   @customElement('my-comp')
   export class MyComponent extends LitElement {
     static styles = [
       IconStylesComponent.styles,
     ];
   
     render() {
       return html`
         <span class="material-symbols-outlined">search</span>
       `;
     }
   }
   

None of these methods worked. Which piece of the puzzle am I missing?