CKEditor / wysiwyg for public profile
[civicrm.root] wrongly evaluated on Joomla. See: https://lab.civicrm.org/dev/joomla/issues/5

A fix for your particular issue is:
Create an override file in your Custom PHP Directory for CRM/Core/Resources.php

On Line: 738 
CHANGE:

'wysisygScriptLocation' =&gt; Civi::paths()-&gt;getUrl("[civicrm.root]/js/wysiwyg/crm.ckeditor.js"),


TO:

'wysisygScriptLocation' =&gt; Civi::paths()-&gt;getUrl(Civi::settings()-&gt;get('userFrameworkResourceURL')."/js/wysiwyg/crm.ckeditor.js"),