Separate keyboard for shortcuts on linux (two keyboards,two layouts)
You need to use
xinput --create-master SecondKeyboard
to create a separate master keyboard, and then reattach the second keyboard to the new master:
xinput --reattach "Keyboard Id" "Master Id"
You use the ids from
xinput --list
This way the keyboards are separate and can be treated exclusively. E.g. you have two focuses, you can write in two applications at the same time with two keyboards, and set different key mappings, by specifying different master ids in things like setxkbmap.