I'm making a midi quantizer & I want to change root note without transposition

Hi,

I followed a tutorial for a basic quantizer and improved it so now it's able to choose one of 7 modes of the major scale (and display the mode name) and everything works as intended (I'm sure there is a simpler way to do this but I'm a beginner so it'll do).

But I can't imagine something to dynamically change the root note. I could just say +7 if I want G but it'll transpose the whole thing, not scale it.

I just want a box with a menu in my main sequencer and select, say, "G#" and "locrian" and the instruments in the patch will play G# locrian. I'm sure there's a solution but I'm struggling, any tip ?