Nah, he is ONE of the most decorated amateurs ever. Not putting Lomachenko down, because he is a magnificent boxer, but:

Just because he is the most recent amateur to win lots of stuff doesn't make him suddenly the best amateur that ever existed, or even the most decorated.

Stevenson, Savon, Papp, Rigondeaux, Kindelan ......

(not even mentioning the fact that just about every professional fighter who ever lived was at some point an amateur too)

That would make Rocky Marciano, Muhammad Ali, Joe Louis, Foreman etc pretty successful amateurs too.....