I’m not certain that wo american entrance into WW2 the Germans would have lost.
The fact is that after Stalingrad the Russians never stopped pushing the Germans back to Germany. This was done wo too much american help.
By the time americans landed at Normandy Russians has already driven the Germans pretty far back and the end was clear.
This is not a criticism of the Americans bc the bombing campaigns that preceded D-Day were crucial to ensure a safe passage across the channel. I.e. if the Luftwaffe had air superiority or even been a nuisance the crossing would not have been possible. It took two years to prepare the way, so to speak.
The point is, the Russians were essentially fighting the Germans alone for 2.5 more years and winning on their own wo american help.
One can even make the argument that allies invaded France not so much to free Western Europe but rather to prevent the Russians from conquering western Europe (a legitimate goal in and of itself)
Unless you taanah that the bombing campaigns disrupt German production so much that it affected the German war effort against the Russians. Is that true? Was that a goal of the bombing campaign?