How do you even turn this on???
This is the second time I've tried to use 2FA. Here's what happens:
I turn it on on my iPhone, which I think is the most "Apple" of my Apple devices.
It then tells me that it's waiting for approval from my other devices.
This never comes because none of my other devices have 2FA enable/authorized yet.
So I try to "Continue" to set it up on my MacBook Pro, which is dutifully telling me to click "Continue" to set up 2FA.
The 2FA message appears on my still-unapproved iPhone. I "Allow" and put in the code on my MBP.
It still tells me to "Continue." I look at my iPad. It also wants me to "Continue."
However, since not one single device has successfully been authorized, not one single device can approve the others.
So I go back to password-only, change my password to a new impossible one, and then run around the house re-logging in on everything. Also, to do this successfully, I paradoxically have to tap "Continue" on setting up 2FA, which then asks for the new password, and then successfully turns 2FA OFF.
There is no way that I can see that one can actually enable 2FA when already using iCloud extensively. It's a clusterf---.
iPhone 7, iOS 12