Perhaps I can help you out with the german keyboard part? I just need to know what you need and how to get that information. :-)
One of my future plans is to migrate the game over to the SDL3 library. Taking a quick look at the wiki, it seems like that library has better support for different keyboard types, so I will probably hold off until I makee the big move.
Glancing at a diagram of the German keyboard, it looks like the ; and : are where the < and > are on my keyboard, so maybe that works. Remember you can also use the mouse to click on things in inventory, click on commands on the side bar, or right click to bring up a commands menu.