Ubuntu 18.04.6 (course build); "Launch QGC with DK script part3" mode GUIDED loop hanging (launchSitl basic_template.py)

There is a lot here. Perhaps you can list your questions in a simple fashion.

Also see this post:
https://community.dojofordrones.com/t/mode-setter-py-getting-hung-up-on-waiting-for-guided-mode/138/7