I hope this is allowed because though I'm not writing an in-depth comment, the books I'm recommending are thorough.

There's a 3 book series by the author Nigel Hamilton that takes a look at the allied planning and discussions from the perspective of FDR, happening from slightly before Pearl Harbor to when FDR died.

The author pulled from diaries, notes, and minutes from the people involved in order to try and rebut the more...let's call it glorified view that Churchill released in his 6 book series after the war. Long story short, FDR was constantly battling the unrealistic planning of his own staff who until Operation Torch had never fought the Germans, and Churchill's regular manic fantasy ideas for how the war should proceed as well as Winston's absolute fear of committing to a cross channel invasion.

Churchill's objection to the cross channel invasion plans at times were bordering on sabotage of the Allied war effort as he was constantly pushing for invasions through terrain that was impassible, focusing on meaningless symbolic goals like taking Rome, or pushing for seizing Greek islands and trying to bring Turkey into the war on the side of the Allies so that the Allies could move up through the Dardanelles to attack into the eastern Balkans. Churchill was absolutely obsessed with the idea to the point that on a number of occasions it nearly fractured the alliance and the Allied war effort.