Trying to load website name and page-title in h1 tag

Hi,
i added this code to function.php:

function add_dynamic_hidden_h1() {
    if (!is_admin()) { 
        $page_title = get_the_title(); 
        if (empty($page_title)) {
            $page_title = "Unbekannte Seite"; // Fallback
        }

        echo '<div style="position:absolute; left:-9999px; top:-9999px;"> 
                <h1>My Website - ' . esc_html($page_title) . '</h1>
              </div>';
    }
}
add_action('wp_body_open', 'add_dynamic_hidden_h1');

As my layout has very less text, because of design reasons, i’m trying to add “My Website -” as h1 (almost for seo reasons) and to load the page-title next to it.

In my source code it looks like this:

<div style="position:absolute; left:-9999px; top:-9999px;"> 
                <h1>My Website - Explore</h1>
              </div>
	<div id='wrap_all'>

Which is what i’m trying to archive.

Unfortunetly, when i go to Google webmaster tools and do a live test, i get something different:

<div style="position:absolute; left:-9999px; top:-9999px;" aria-hidden="true"> 
                <h1>My Website - Explore</h1>
              </div>
	<div id="wrap_all" aria-hidden="true">

Which seems not to works for seo?
How can i fix that?

kind regards
Jak