Fair enough, I can’t comment on Duo because I have no experience. As far as iOS and macOS goes, you can receive as many 2fa popups as you have trusted devices, all at the same time. They all react when one is used, disappearing from the other devices, but they all get the original alert.

Two-Factor is best when you have more than one trusted device and/or trusted phone number. Just two of one of them means you can pretty much always get codes. And the phone numbers mean your android works, too.