I wonder what Alexander the Great would think about this. Did he think he achieved greatness? Was he happy and satisfied? Or did he suffer from the impostor syndrome like many "greats" of today?
Whether he was happy or satisfied or suffering imposter syndrome feels like attaching modern sentiment to classical times. Dude murdered people by hand a lot and drank himself to death. I don’t think he was happy or satisfied, and I think he would laugh at the concept of imposter syndrome.
(Plutarch)
(But as far as we know he did think he was great. "Only sex and sleep make me remember I am mortal", "If I were not Alexander I would wish to be Diogenes", and so many other lines suggest he thought he was awesome, note those quotes are my paraphrasing.)
Still, to me, Alexander's father was the man who made Alexander, so he was greater. (I don't mean by birth, the army and previous conquests)