Maybe I am misunderstanding something. You are of course correct that you can map different scancodes to one or many keys, so it’s not a 1:1 mapping. But I am not talking about the configuration part of Agent (where you assign something to your keys).
Forget about Agent for now. Let’s talk firmware only.
tapKey r will tap exactly 1 key, so it’s name r maps 1:1 to the key id of the key that carries the legend r on the US keymap. So that’s why I am referring to this as a 1:1 mapping. That’s what I mean with fixed relationship.
I’d like to extend this, so that tapHostKey r will consult mapping tables so that it picks that key which will produce the r character on the host.
As @mlac suggested, I will open a new topic for this discussion. See you there!