Who achieved the most and the least of the Fellowship?

In Unfinished Tales, in an essay titled "The Elessar", Tolkien wrote that "Legolas probably achieved least of the Nine Walkers." The full paragraph is quoted below:

Elendil and Gil-Galad were partners; but this was "the Last Alliance" of Elves and Men. In Sauron's final overthrow, Elves were not effectively concerned at the point of action. Legolas probably achieved least of the Nine Walkers. Galadriel, the greatest of the Eldar surviving in Middle-earth, was potent mainly in wisdom and goodness, as a director or counsellor in the struggle, unconquerable in resistance (especially in mind and spirit) but incapable of punitive action. In her scale she had become like Manwë with regard to the greater total action. Manwë, however, even after the Downfall of Númenor and the breaking of the old world, even in the Third Age when the Blessed Realm had been removed from the "Circles of the World," was still not a mere observer. It is clearly from Valinor that the emissaries came who were called the Istari (or Wizards), and among them Gandalf, who proved to be the director and coordinator both attack and defence.

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I first thought the line seemed a non-sequitur but now that I reread it it's in the midst of Tolkien making a point about the relative "non-involvement" of the elves in Middle-earth towards the end of the Third Age. It almost seems like Tolkien is suggesting Legolas was purposely holding back from acting, which strikes me as curious.

Anyway, that's not the point of this post. As per the title it's to ask who did the most of the Fellowship and who did the least. A question on Quora asks if it's Pippin, which I don't think is the case. But I'm curious to see what others think.