Plesk has released a new paid addon that allows you to centrally manage the Joomla can manage installations.
The Plesk Joomla Toolkit
Similar to the WordPress Toolkit the customer can manage his Joomla installation without logging into the Joomla backend.
The current version is still a bit slow and does not offer any options to e.g. disable single plugins and templates, but it does offer a way to check the current version and see if there are updates.
If you use Joomla correctly, you probably use more extensive maintenance software, but this toolkit is suitable for beginners, or gives the reseller or administrator a good overview of the installed Joomla instances and can bring customers to update your site in that case.
The Joomla Toolkit Dashboard
Via the dashboard of the Joomla installation you can now log directly into the backend, edit files with the File Explorer, or edit the database directly in phpMyAdmin. It saves a few clicks in the Plesk interface.
Below that you will see some information about the installation like the Joomla version, the installation path and the name of the domain, as well as some information about the used PHP and Mysql version.
On the right hand side there is information about the installed extensions, database information and the configuration entries.
At present, this does not have any real benefit. The WordPress Toolkit has much better settings so that you can deactivate a defective plugin via Plesk and then log in normally.
These functions will hopefully be added. Then you can have your Joomla updated with Plesk.
However, experience shows that at least one backup is required here, because in many cases Joomla can be rendered unusable with an update.