There is a difference between self proclaimed hype(that could be an act of arrogance) and a hype coming from other characters(that generally represent the perception outsiders have on a certain character). Doflamingo is the one who created hype on his boy. He said Luffy had better potential than Law, and despite knowing Vergo lost to Law, he still thought Diamante would win. He had so much confidence in his strength that he thought he could even handle a yonko commander(Burgess). Unless Doffy was an idiot, that hype was clearly not worth it, assuming it's really all what he can do, that's it
