> Just look at the Boeing 737 MAX. That is the best example for an unstable aircraft.

No. Not in the aerodynamical sense.

The Boeing 737 MAX is stable. In this sense: "The term stability refers to the tendency of an aircraft to remain in, or return to, the trimmed flight condition after a disturbance." It means that if there is a tiny gust of wind which buffets the aircraft and the pilot doesn't have their hands on the controls the aircraft will return to the original flight path, or keep the new flight path, as opposed to turning belly up and then crashing out of the sky.

Examples of unstable aircraft (in the aerodynamic sense): F-16, F-22, B-2 Spirit, etc

With these if a gust of wind upsets them, the aircraft needs to adjust control surfaces to don't fall out of the sky.