Existing Accessories, HomeKit Router

Hi everyone!

I’ve been considering purchasing a HomeKit enabled router. I have several existing HomeKit accessories and I have some confusion over the documentation that Apple provides.

The Apple support document states;

“After setup, add your HomeKit accessories to the Home app. If you already have HomeKit accessories added to the Home app, they will continue to work and benefit from most HomeKit network protection features. For even more security, remove and reset your Wi-Fi accessories then add them back to the Home app. This creates a unique passkey known only to the router and each accessory.”

Obviously, given that I’m interested in a HomeKit router, I’m concerned about the security of HomeKit devices, so I’d like to benefit from the most secure setup that HomeKit provides. But it isn’t entirely clear what is required to properly proceed.

Is it just Wi-Fi enabled devices that need to be removed and added again to the Home app? Do Ethernet devices (like my Philips Hue bridge) need to be removed and added again? And if so, do the accessories that communicate through the bridge need to be removed and added again? Or just the bridge?

What about accessories that communicate with a bridge that is Wi-Fi enabled (like my Netatmo thermostat and radiator valves)? Do I need to remove and then add just the bridge? Or all of the accessories?

And do I need to factory reset the device(s) entirely? Or do I just remove them from the Home app and add them again?

Many thanks in advance to everyone that responds.