I wish I knew. Having an actual opinion on an actor's skill can be tough. Arnold is said to be a bad actor, but someone he's successful AF anyways.

Marlon Brando. The best modern day actor is Gary Oldman by a long-shot.

Tom Hanks

idk, maybe Ben Kingsley

David Jason

Sidney Poitier

I'm not old enough to judge those older than my teens ... though having seen old movies I'd say probably Helen Mirren stands out a lot!