Matter needs two things you may already own — a controller (Apple Home, Google Home, Alexa or SmartThings hub) and a Thread border router — and then setup becomes scanning one QR code.
You can't turn off the wake word and keep the assistant — but you can delete the recordings, mute the mic on command, and decide who reviews what, in each platform's documented settings.
A retrofit smart lock keeps the existing deadbolt and key — renters get smarts without replacing hardware, landlords get codes they can expire remotely.
Change the admin password, apply the firmware update, kill WPS — the documented half-hour that closes the three openings attackers actually use on home routers.
The ecobee Smart Thermostat documents a remote sensor in the box and works without a C-wire in most homes — the two spec lines that decide a thermostat purchase.