For there to be an “American Homer” the answer would have to be immediately obvious to everyone, to such a degree that doubting it would immediately mark you as an eccentric. E.g the Italian Homer is Dante. So that this is even a question shows there isn’t one.
I think this is what lord of the rings really succeeds at and it makes the movies that much better because I'm never watching and think "That's [actor]" like everyone embodies their character so well it's insane