Show action buttons (as well as preview content toggle) that are on layout builder page

Playing around with this a bit ... if you are using the Gin admin theme, and Gin Layout Builder module, you can get it working. The module provides an alter hook that will let you specify which routes it should apply to, so:

function MYMODULE_gin_lb_is_layout_builder_route_alter(bool &$is_lb_route, array $context) {
  if (\Drupal::routeMatch()->getRouteName() === 'entity.node.edit_form') {
    $is_lb_route = TRUE;
  }
}

Will get you the Gin layout builder sidebar, with the content/region preview display option widgets in the Gin secondary toolbar. It's a start...