You need to explain what exactly you mean or are referring to. I have AT&T and yes, I have wifi calling as a feature under my “phone” settings. Wifi calling is a carrier feature and has nothing to do with google. If your carrier, plan and device support it, then wifi calling will be in settings. Otherwise not.
If you are referring to some sort of VOIP calling, you need to clarify your post.
Fi.Google as a service was never available for iPhones. Fi was an Android device only service. Google isn’t interested in supporting iOS iPhones. They are the publisher of Android, so are interested in furthering their own mobile operating system, not someone else’s.
https://fi.google.com/about/phones/?