Why can't you bind "Ctrl+m" and "Return (enter)" to different actions?

I don't know if I'm bad at searching for information on the internet (even tho I tried for the last 2-3 hours), but I'm not able to find how I can bind Ctrl+m and Return to different actions. I have found how I can "unbind" Ctrl+m but it also unbinds the Return key and I want to use it.

Why isn't this possible? Are these two "connected" or something like that? Is there a "hack" to achieve what I want?

If not, is this an "operating system" thing or something that I can create my own shell and/or terminal library and change?

EDIT:

I have tried the following: Quote:

bindkey -r '^m'

This unbinds the "Ctrl+m" key as expected. However, "Return" does not work as well. Hence, my question about them been "connected".