@Capt_MorganCreek Hey!
Thank you very much for the file and the Help!
I had to change a little bit in the Script and use now uinput from uinput.
I ran into Problems with Dependencies... basically I haven't read thoroughly enough...
Everything else in the Script is the same.
Software works and the Buttons also... but! I have to make a new Plan on the Hardware itself.
It turned out that the Way I wantet to build the entire Thing does not work. It just does not fit...
Will have to see when I will have enough Time again to make a new Plan...
Big Thanks for the Help!