I kindly suggest you to rewrite your request using a single and clear question with a descriptive title to allow people to help you. As you indicate within your notes (VServer, subdomains, Ubuntu, Plesk), your issue seems to me more related to server administration.
You can also get help in "all direction", in German and so, hire a consultant. 🤷🏻♂️
There is also a Tiki manager to more control and ease managing several Tikis.