Looking at the Buddhist scriptures it’s hard to ignore the Buddha’s “Lion’s Roar” where he declares that he is awakened.
People would say this reticence was an “eastern thing” - a sign of how spiritually mature Asia was, because of course you would “just know” that someone was Enlightened. Enlightenment used to be something of a dirty word in the west, or at least it used to be considered improper to make any claims to be enlightened.