add_action('wp_dashboard_setup', function() {

    global $wp_meta_boxes;

    unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_site_health']);

});

add_action('admin_menu', function() {

    remove_submenu_page('tools.php', 'site-health.php');

});

add_action('wp_dashboard_setup', 'remove_wpseo_dashboard_overview' );

function remove_wpseo_dashboard_overview() {

  // In some cases, you may need to replace 'side' with 'normal' or 'advanced'.

  remove_meta_box( 'wpseo-dashboard-overview', 'dashboard', 'side' );

}