Thank you for contacting Dell. We have sent you a private message. Please check.

For the record, the private message, from someone named Nimin, said to click "Text me a one-time code" when signing in. But that only sends a text for that one sign-in. It does not change the default or preferred method to text.

When I pointed out that those instructions do not solve the problem, Nimin wrote the following.

"You are right. Even while we check Dell My account settings, it does not give an option to make Text as the preferred method for receiving the 2-factor authentication (2FA) code.

"Since your account is linked to your email address, it will always send the one time password to the registered email address as the default method. The Text method is an add-on option to complete the 2-factor authentication. We do not see any option to set the Text option as the preferred to default 2FA method. It will have to be manually selected on the Two-Step Verification page."

In other words, there is no way to do what the Two-step verification FAQ says you can do (quoted in my first post above).

Either Nimin is wrong or the FAQ is wrong. The problem remains unsolved.