I just bought a Montage and want to do the same thing that someone was requesting - change Scenes with a foot pedal.
One response in this forum was that "you don't need that".
I have an OASYS and use a foot switch to change scenes. It is useful. It is a choice in Global settings. So, Korg thought it as important enough to offer 10 years ago.
Are we sure that the Montage can't do the same?