Siri HomeKit on Apple Watch

Good morning all, I recently purchased the Apple Watch Ultra 3. I am unable to control smart home / HomeKit accessories using Siri in my watch. Yet I am able to do so using my iPad, iPhone and MacBook. I’ve tried resetting WiFi, Bluetooth and even factory resetting the watch but have unfortunately had no success. I get a range of different error messages from Siri when trying for example to turn lights on/off. Including “None of your accessories can do that” “None of the lights in your home have power control”

Its not a dealbreaker, just a bit irritating as Siri tends to default to my watch over my iPhone whilst wearing it.

The watch is fully updated. Some users reported similar issues and advised logging into iCloud however my watch appears to already be connected to my iCloud account. I’d be grateful for any suggestions.

Thanks in advance!