Gradey is a magnitude of order better athlete than Milan, in terms of explosiveness. He's also listed as 2" shorter and 15# lighter than Milan.
He's on the Raptors roster after being taken with the 13th pick, but he hasn't played much, ~12 minutes a game and has only played in half their games. He's shooting 24% from 3 and 35% from the field.
I think there's very different answers as to whether Milan could get drafted, should go pro, or will. I don't think he will, or should, but it's really hard to predict anything in the current CBB environment