OK. So the code works for 6 piano keys each of which has two tactile button switches.
Now you want to extend it to all piano 61 keys on the Yamaha keyboard.
Q1. Is that correct ?
You have shown this picture.
Q2. Is this the Yamaha keyboard ?
Q3. What are the 2 small blue circuit boards connected to the wiring ?
Q4. You have shown pictures of the tactile buttons behind the keys but these pictures appear to have been taken from MIDI keyboard with velocity sensitivity (PASSIVE version) - #10 by petelms . Is your keyboard identical to the one in that thread ?
Q5. Did you get the contents of post #18 from a web search or ChatGPT like tool ?