Unable to connect to simulator. What am I doing wrong?

Somehow I can't connect to the simulator. There is not even a window popping up and I get no further error information than "Unable to connect to simulator." in the Debug Console.

I tried several things that were mentioned in older threads but can't find the answer to my issue.

I'm on Ubuntu 20.04, Garmin SDK 4.1.4 (also tried other versions) and Java 11 RE. Also tried to install them in different orders and with different versions, but the error seems to be somewhere else.