There's a difference between a MITM proxy in front of a huge portion of the web and a password manager that's running locally on a personal machine. Also there

There's a difference between a MITM proxy in front of a huge portion of the web and a password manager that's running locally on a personal machine. Also there's the 2-factor stuff to protect you when you somehow lose your manager's master password. What protects you when the proxy in front of you misbehaves and exposes your shit?