hidmacros.eu

if I have 2 devices like 'Kb1' and 'Kb2',
I can use Kb1 Q to trigger E on Kb2 and vice-versa?

or even use a keyboard to trigger and button or axis of a joystick?

No.

You can send "general" key strokes but these are "faked" and stored directly to windows queue so cannot be handled by hid/lua macros again.
Similar to joystick... how do you "trigger" axis? You probably mean to have some virtual joystick and control it from luamacros. I saw some software with this feature (creating virtual joystick with API) but never needed to use it.