Adding Widgets to Draft Pages

As you note in your comment there are plugins that allow you to insert different widgets on different types of pages. If the plugin doesn’t include the possibility you need, you’ll have to build it yourself.

First, you’ll have to familiarize yourself with how to add widget areas (sidebars) to your (child) theme. It isn’t that difficult. You will learn that after some work you’ll get an extra sidebar to fill with widgets in the admin area and that you can insert that sidebar in your theme with code like this:

if (is_active_sidebar('my_sidebar'))  // test if there are widgets in the sidebar
  dynamic_sidebar ('my_sidebar'); // display the sidebar

Now, you want to show a different sidebar for draft and published posts. You can easily do this by testing for the post status using get_post_status and display a different sidebar depending on the result, like this:

$status = get_post_status();
if ($status == 'draft') {
  if (is_active_sidebar('my_draft_sidebar')) dynamic_sidebar ('my_draft_sidebar');
  }
else {
  if (is_active_sidebar('my_sidebar')) dynamic_sidebar ('my_sidebar');
  }

Beware that if you have stuff like a ‘recent post widget’ your draft will likely not be shown, because the widget only checks for published posts.