Alternative to RedirectResponse
Generally speaking, directly redirecting from a hook is something you should not do because it would not allow other hooks to be invoked, and it would stop what Drupal is doing.
In the specific, hook_node_insert() would also be invoked when a node is programmatically created from a module, for example in a hook_install() or hook_cron() implementation, or from a Drush plugin. In those cases, redirecting inside hook_node_insert() would just break Drupal core or third-party modules.  

If you want to redirect users, the proper moment is after a form has been submitted. It is also preferable, because you can tell Drupal where you want to redirect users, and Drupal will do it after all the involved hooks are invoked.

You just need to add a form submission handler to the node edit form. Inside that, you redirect users with $form_state-&gt;setRedirect($route_name) or $form_state-&gt;setRedirectUrl($url) where $route_name is the name of the route (a string), and $url is a \Drupal\Core\Url object.