> ... each additional authenticator makes it easier to attack you (meaningfully more guessed codes are now correct at any moment) ... That isn't really an issu

> ... each additional authenticator makes it easier to attack you (meaningfully more guessed codes are now correct at any moment) ... That isn't really an issue with TOTP either (if properly implemented), as each authenticator has a unique identifier and seed. I've got multiple authenticators set up on a PayPal account. When logging in, I simply select which of the authenticators I want to use and enter the code it gives me.