Possibly contrarian point of view: a) Passwords should be easily rememberable. Pick four words are string them together (e.g. correcthorsebatterystaple). b) You must have a physical security key to authenticate - a Yubikey etc. If those two factors are not enough, then forget working from home / mobile authentication - require people to arrive in-person and work in-person, with network restrictions on top of the two-…
>network restrictions on top of the two -factor authentication That is exactly what I thought was the case too until I recently entered the code Google Authenticator gave me although my mobile was not connected to the internet. And it worked.
TOTP is supposed to work without a network connection.