have a copy of values of post_title in my post_content

hello wp commuity ??

I am wanting to have a copy of the title in my content, and not simply want to duplicate the the_title (); in single.php, because this does not make the title value available in dasboard, I duplicate the title to have it in my content but available in post edit. have a copy of values of post_title in my post_content

add_filter( 'wp_insert_post_data' , 'get_post_title' , '999', 2 );
function get_post_title( $post_content,  $postarr='' ) {
$post_content['post_content'] .= $post_title;
    return $post_content;
}

I want to do this in all my posts.

thanks to all.