Admin User Interface as backend for front-end CMS

Hi,

In my project, we have front-end website developed already.

I want to build admin side application using CMS.

I check following admin templates.

[1]. https://www.webappers.com/2009/09/18/20-professional-web-admin-templates-on-themeforest/

https://www.tripwiremagazine.com/2012/12/admin-templates.html

[1]. https://ignaciogiri.com/emanager/

[2]. https://themeforest.net/item/smooth-a…preview/101529

I want to develop admin CMS applications using WordPress, Drupal or Joomla.

I will not develop front-end of the application but backed admin using CMS.

I want know it is doable to create Admin User Interface as backend for front-end CMS using WordPress, Drupal or Joomla.

Any Idea?

Thanks & Best Regards.