The site needs to be renewed. The reason for this change is to write posts in English too, as that would require more custom code and I don't have time for that right now. To save my time I've decided to go for CMS. I'm pondering between Joomla, Drupal and Wordpress. Each of them seems to have their own pros and cons but right now it seems that the Wordpress will be my choice due to rapid deployment and lots of plugins to choose from.
Whatever my choice will be, it needs to support MariaDB and Nginx. Drupal and Wordpress have official statements that they support MariaDB but I'm not sure about Joomla. MariaDB is (still) a drop-in replacement for MySQL so I assume it will work with Joomla too.