Any system that is connected to the Internet is always subject to threats, no matter how well it is protected. This assumption is well known to any teenager today. No software barriers can fully prevent human errors in a program code or user behavior.
That’s why devices that have functions of special importance, or that contain top-secret information, are usually not connected to the Internet. It is always better to accept inconvenience than face unpleasant consequences. This is how, for example, control systems for large industrial objects or some bank computers are protected.