How can I set a key binding that globally overrides and takes precedence over all other bindings for that key? I want to override all major/minor mode maps and make sure my
I don't think you can. That is roughly equivalent to saying that you want to define a global variable that cannot be hidden by local variable declarations in functions. Scope just doesn't work that way.
However, there might be a way to write an elisp function to go through the mode list and reassign it in every single one for you.