I’ve got a Benq X-Touch 122 keyboard with Swiss German layout. Apparently this is a very rare species, or how else would it be possible to not get it right?

The shortcut on the front of the “Y” key is wrong; Undo is Ctrl-Z (or Cmd-Z), not Ctrl-Y. It is true that the “Z” key sits to left of the “X” with many layouts (the QWERTY ones), but not with with the German QWERTZ layouts.