Add Drupal <!--break--> insert button (teaser break)

Problem/Motivation

Hi and thank you very much for this wonderful module with these great features!

One thing that's missing for Drupal since Drupal 8 (D7 had it) is being able to add the Drupal teaser page break <!--break--> in the Editor using a button.
https://www.drupal.org/project/ckeditor_drupalbreaks → implemented that functionality in contrib, but seems to be no more maintained and is based on https://www.drupal.org/project/fakeobjects → which has no D11 compatible release and also seems to be unmaintained.

As it's a super simple, but helpful feature, it would be great if you could consider adding it as further addon.

Thanks!

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes