The difference between hero and protagonist.

Frodo, the Hero, is the pawn of Fate. He does not actively choose the Quest, but passively accepts it, as if another is speaking through him, and Elrond confirms he is destined to the task. Once he has completed it, he is broken and diminished. Even upon his return to the Shire, he is little more than a passive observer of events. He receives little admiration or respect from his own people, and eventually leaves the world (dies, to all intents and purposes).

Samwise the Protagonist chooses the Quest freely, of his own will. By the end, he has become wiser, stronger, a more powerful person, capable of leadership. He is respected among his own and lives among them as a leader for many years.

The Hero is a pawn. Chosen at birth, propelled along a destined path by forces he can neither comprehend nor resist. When all is done, he is cast aside like a worn-out tool, to rust away in obscurity or be casually destroyed. He is the personification of the vegetation or the Sun in ancient cults.

The Protagonist is a human being. He acts of his own will and makes his own choices. He may fail or succeed, but only through the choices he makes. He can defy Fate or the Powers. Win or lose, he does not surrender his selfhood or will.

No human being was ever a Hero. Heroes belong in myth, they are symbols, stand-ins or signs for inevitable natural cycles.

But all of us, if we so choose, can be the Protagonist or our own story. We need only decide to defy absurdity and expectations, and live authentically according to our own ideas and beliefs - whether those beliefs are right or wrong is largely irrelevant.