Concrete5 or Drupal/Backdrop as a wordpress alternative

I recently received a notification that a government agency in my country has started to ban Wordpress (and Joomla) CMS and they are giving me the option to choose a tool for an upcoming development project.
So I wanted to ask you, if you were in my situation which alternative tool would you choose?

Do you mean like for government projects? If they ban WordPress and Joomla then I guess they have to ban all the other open source CMS, since it wouldn’t make sense to ban only these two, which will leave you to only custom-coded CMS.