Change node configuration dashboard UI settings
You can't do this in the UI, you need code.

You could attach some JS to open it, but it's much easier to create a module with a form_alter and then you can make the element expanded by default.

https://api.drupal.org/api/drupal/core%21modules%21path%21path.module/function/path_form_node_form_alter/8.2.x defines the element, you can see that it defaults to open when there is an alias already.