Your milage will vary with your corporate policies.

What does this have to do with anything?

I can’t just pick up any smartphone and install a passkey manager on it.

Sure, because “any smartphone” includes smartphones that don’t turn on, that are locked with a passcode you don’t know, or that are running a 10 year old OS.

Which modern smartphones (meaning, still supported by its manufacturer and running a current OS, i.e., iOS 17/18 or Android 14/15) don’t have passkey support? I don’t know of a single one.