Does a restart count as "signing out" of Apple ID account, requiring Two-factor authentication to sign back in?
I turned on "Two-factor authentication" three days ago for my Apple ID account.
From what I understand of it, having Two-factor authentication turned on means you need to have a second "trusted device" also signed in to the account in order to receive a six-digit verification code sent to that other device, which you then enter into the device you're signing in on.
My main question is simple:
If you're using a device (Mac or iPhone), are signed in to your Apple ID account with Two-factor authentication enabled, and then you "shut down" or power off -- does that mean that when you power it back up or restart, the act of restarting means that you have logged out of your Apple ID account, and will require the Two-factor authentication six-digit code to log back in to your own account?
If so, does that mean that one ALWAYS needs to bring two Apple devices when traveling, and always leave one powered on, so that you will be able to receive the six-digit code on the other one in order to log back in to the one that's powered off?
If not, does that mean that once a person has ever signed in even once on a device, it is always remembered as a "trusted" device, even after having been shut down?
My secondary question is:
I see many articles and support questions saying that once Two-factor authentication is enabled, it can never be disabled. But some sources say that there is a two-week grace window, where you can turn it off if less than two weeks have passed since you first enabled it. Which is true?
iPhone 12 mini