I will say this about FDR. He was probably the best leader of a major power during WW2. Far better than Hitler, Stalin. Mussolini, Tojo or Chaing. And yes, even better than Chruchill, who, despite his ability to inspire his people, had some hare - brained ideas and tried to duck challenging the Germans head on.
FDRs accomplishment was in surrounding himself with top-notch military talent and allowing them to go win the war their way. None of the others did that.
Domestically, I don’t approve of his policies. He lacked Churchill’s vision for a post-war world, although many of his policies set the table for us to dominate the peace. But he did know how to win a war in a way not matched by most of his successors.