I think you’re not quite understanding what I am saying…
You don’t need to control the light fixture, just the switch, which is why you don’t want to use “smart bulb” mode.
If you enable Local Protection, the switch will no longer allow you to control the relay in the switch by pressing the buttons.
Instead, you use the paddle or favorites button presses from the switch through Apple HomeKit to turn the relay in the switch on or off through automations.