I had a chat with a support technician some days ago. He told me, that Drupal and Joomla are “deprecated” and will not be available as installable packages in the future
Nevertheless, you can still install Drupal easily by setting aup a PHP custom app. Justo connect via SFTP and delete the index.php from public_html folder. Upload the newest Drupal or Joomla as a zip or tar and extract it via SSH connection. Go to you application URL and the manual install will start. You just have to fill in you SQL-connection data an will have Drupal or Joomla installed within a minute.
The really annoying thing about this is, that the preconfigured Drupal packages came with drush out of the box. And drush will not be installed if you just create a PHP application.
I opened a ticket about that topic recently and still waiting. Would be really sad, if Cloudways goes the direction everone else goes and becomes just another Wordpress hoster. For me, not having drush would be a huge dealbreaker which would lead me to change the hoster.
Hope there will be a solution soon, or some people might move their application to other hosting providers.