So I created one input which turns out to be an output:
What is wrong here?
Nothing is wrong…
When you create an "input" (aka control) in the dialog's user interface then you get its value as an output in the conpane of the ExpressVI!
The English name of that function is "prompt user for input" - and that's what it does! It prompts the user to input data - but not the programmer in the block diagram…
(Similar to your other threads: what are your expectations for that ExpressVI and how good do those expectations match with the help for that VI? Maybe using the English LabVIEW version would help you as some functionality is localized quite bad for German version…)
Best regards, GerdW
using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019