Use iPhone as FIDO Security Key with Google Accounts and Advanced Protection

Unfortunately they released it without any testing and it cannot be used. Here's what happens if you try to enable Advanced Protection:

1. Enable the Smart Lock app, add it to your account, use it to login 2. Enroll in APP 3. Notice that the Smart Lock app was automatically removed from your account 4. Attempt to authenticate, and see that the login process requires Smart Lock and actively prevents the use of hardware security keys (my FIDO keys work on desktops, and via NFC on other sites in iOS), does not allow TOTP codes, and does not accept g.co/sc codes from other trusted devices.

The most annoying point is #4 since “use a security key” would work if the app used the built-in FIDO support.