"And the chord track switch you mentioned is now available. It means that every time the chord is updated, the remaining notes are retained. But how does this note control the switch? I don't quite understand. Can you make a video? Thank you"

Perhaps learn what keyswitches are before asking questions like: "But how does this note control the switch" . Keyswitches are for 3rd party VST2/VST3 instruments. Bottom line is, if you don't manually draw keyswitches they will not alter your chord track in any way.
I don't know good tutorials on keyswitches, but you can try watching this:

Somewhere in the middle, it shows how keyswitches are used.