What happened to the ability to use the Fn key on the keyboard to modify the actions on the mouse? Even if you are enabling more comprehensive customization on the mouse alone, having a Fn modifier to add a completely new set of actions just makes sense. Frankly, I wish you had different modifiers than just the Fn key. On MX Keys for Mac, the Fn Key is toward the right side of the keyboard, which means reaching across the keyboard with my left hand while using my right to navigate my MX Master 3 for Mac. Being able to use something like the Control, Option, or Command keys to modify actions on the mouse would be nice because they are available in the bottom-left of the keyboard.