The greatest ever composer? It’s between Ludwig and JS Bach in my opinion. Greatest human being ever? I think so. Beethoven wasn’t some general of an army slaughtering thousands of conscripts and innocents. Then again he didn’t advance medical science or invent some amazing machine. But he was one of the first composers to break free from the aristocracy and elevate musicians above the level of servitude and write music because it had to be written. Yes, Beethoven had patronages from the wealthy but it was done on his terms, and his terms only.
He thought about man being free in a way you wouldn’t expect from a composer. And most of all he thrust music into the future quicker that can be imagined. Music had slowly evolved from the baroque to the classical Beethoven took it is innovative new ways. The powerful use of motif is expertly displayed in the first movement of his fifth symphony.