I'm sorry for awakening an old thread, but as this subject came up first in my Google search, I thought it would be wise to share a proper solution regarding the unfiltered_html setting in Cloudron's WordPress managed app.
In the WordPress managed app, the unfiltered_html capability is configured in the wp-config.php file :
define('DISALLOW_UNFILTERED_HTML', true);
to revert this you can just change this line to the following one:
define('DISALLOW_UNFILTERED_HTML', false);
The reason WordPress managed on Cloudron could be a better choice for some use cases, particularly from a security standpoint, is noteworthy. In the managed version, most of the WordPress files are on an immutable partition, meaning they cannot be altered. This greatly lowers the risk of security issues caused by unauthorized changes to the files.
Also, as the WordPress core files are part of the WordPress cloudron app's, they are not included in the Cloudron's backups, making the backups lighter and quicker since only plugins data and customizations are backed up, not the entire WordPress core.