Adding a custom field as a link to an elementor button

Ok, I have been trying to work this out for a while. I don't understand how the short code API should be applied. And should the collected email custom field be an email format, or is it better if it is text?

  add_shortcode( 'make_a_mailto_email_link', function() {
        $author_id = get_post_field( 'post_author', get_queried_object_id() );

   $user_email = rwmb_meta( 'user_email', ['object_type' => 'user'], $author_id );
    if ( empty( $post_id ) ) {
        return '';
    }

    $output = ( 'mailto:'; $user_email );
    return $output;
} );

`

Am I along the right tracks? And what do I need to do to make it work?

Hi Long, thank you for your reply. It didn't work by making it html - but I got it working with:

add_shortcode( 'make_a_mailto_email_link', function() {
    $author_id = get_post_field( 'post_author', get_queried_object_id() );
    $user_email = rwmb_meta( 'user_email', ['object_type' => 'user'], $author_id );
    $output = $user_email;

    return $output;
} );

And adding "mailto:" in the advanced 'before' field in the dynamic options in elementor.

Thank you for your help though! Really happy this ones done!

I went back to a backup to compare metabox configuration and code and plugins - all exactly the same! With the only difference being elementor and meta box updates...