CiviCRM menu disappears and upgrade to 5.23.x fails if Joomla is in a folder below the website.
This issue may also apply to Drupal, but I haven't tried it. If the Joomla site is a subfolder of the main site, e.g. https://www.example.com/joomla, the CiviCRM menu disappears after upgrading to 5.23.x and the database upgrade gets stuck. If Joomla is immediately under the site, both issues disappear. Examining the code shows errors in loading scripts, where the browser attempts to load files in:
In other words, it seems to be duplicating the subfolder.