A WiFi certification usually indicates the update roll out preparation is in last stages. While there's currently no official information on exactly when the update will arrive, leaks and rumors so far have suggested April roll out for the Galaxy S7 Oreo update and May roll out for the other two devices.
Yeah probably...I think I'm going to buy a Google pixel next time
That's probably it. In the US unlocked Samsung phones are known to get updates last. It's probably the same situation for you as well.
My note 8 is sim free. I live in U.K