SMTP is only for sending mail to and between mail servers. Did you mean something else? And no, 2-factor is not the same as a long password, because it is less

SMTP is only for sending mail to and between mail servers. Did you mean something else? And no, 2-factor is not the same as a long password, because it is less likely that both factors will get compromised at the same time. However long your password is, a single software flaw could expose it.