T-Mobile ID: How to get 2 Step Verification code via email

I just set up my T-Mobile ID for my T-Mobile account, via computer, as T-Mobile required me to do.

The account covers two phones. I gave my email address, and signed up one phone as the primary account, that I now use to sign in to T-Mobile. When I sign in, Two step verification sends a 6 digit ID number to the primary phone. That is the only place it offers to send it.

I tried to sign in from the other phone, and from the computer. In all cases, it sends the verification code to the primary phone. There is no option listed to send it to the other phone, or to the email account registered under my T-Mobile ID.

I have already lost one phone, a different phone (or it was stolen). If I lose this primary phone, I won't be able to log in to my T-Mobile account, because I won't be able to get the 6 digit 2 step verification code.

In other words, if I lose my phone, it appears I will never be able to log in to my T-Mobile account again. (That has always made me afraid to use them when offered).

I have searched the T-Mobile website, and can’t find any place to choose a different two step verification alternative, such as sending the code to my email account.

My bank gives me all kinds of choices for two step verification: several phones I have registered, as well as email, any one of which I can choose from when attempting to login.

Surely  the engineering geniuses at T-Mobile can do the same? And put it in a place where I can find it? Does anybody know how to do this with T-Mobile ID?