2FA is becoming a standard, specially for administrator that manage users sensitive data.
A probably faster solution could be to implement google signin also for developers (as you have for users) and allow the developer to disable the standard login, allowing google signin only (that already support 2FA)
We are excited to announce two-factor authentication, or 2FA, for the Knack Builder! (Here's our blog post on it.) Enabling 2FA will add an additional layer of security to your Builder account, requiring you to provide a randomly-generated six-digit code from an authentication app of your choosing.
I would like to see 2FA an option that admin's can turn on. In some cases the users may also be accessing sensitive information and having 2FA would make them comfortable with the security.