lol how, they understand their craft better than anyone else lmao. You can go ahead and say that you like a certain actor best. But that has nothing to do with who is objectively the best at the craft of acting.
Daniel Day Lewis he won three out of six oscar nominee a true genius below him
Robert De Niro
Sammuel L Jackson
Leonardo Di Caprio
James Spader and a few others.
Well I think it's depends on the role. For example no one in the world could've played better Tony Montana (Scarface) than Al Pacino did
But there are many many roles that other actors were just better in than Al Pacino would've been