2 factor is not the same as 2 step. 2 factor is more secure.
Google Authentication can be done via 3rd party app. I use my 1Password actually, which makes Google's method 2 step, not 2 factor.
Apple's "2 factor" works by pushing a system notification to your iPhone. A phone number isn't needed to do this. However, Apple uses a phone number as a fallback if the push doesn't work for whatever reason. This phone number part is what keeps Apple's method from being true 2FA.
Neither Google's or Apple's is true 2FA, but Apple's is more secure because you can't use other apps to authenticate.
Ok... so you haven't explained what real 2 factor authentication is? And I really don't buy Apples system being any more secure when it works in the exact same, way as googles.