Complex sentence: In Hollywood, although Dalio was never quite able to rescale the heights of prominence that he had enjoyed in France, he appeared in 19 American movies during the Second World War, in stereotypical roles as Frenchman.
Split into simpler sentences: In Hollywood, Dalio was never able to rescale the heights of prominence that he had enjoyed in France. Dalio appeared in 19 movies in America during the Second World War, in stereotypical roles as Frenchman.