That looks really useful.
But it is beyond what I can support, but I’ll give you a couple thoughts.
When you installed osTicket Awesome, did your Pfad_zu_osTicket change?
The path to the User Directory in osTicket Awesome is still /scp/users.php
If you followed the osTicket Awesome installation instructions you should have a backup of your original osTicket. So you could try using that path (e.g. https://yourdomain.com/support-old/scp/users.php) to see if that works.
That’s all I can think of. Good luck.