CNZ:
IOS 18 is officially launched but still not locking onto RCS according to About settings.
Thinking its an Apple thing rather than the telcos because it works on basically any Android.
iOS 18 isn't officially out until Tuesday (the 17th).
I don't believe any of the NZ providers support RCS. "Google RCS" is effectively a different thing (it sidesteps the phone companies and uses Google's own servers).