Well, no.
WWII started because Germany and Japan decided that other people had something and they wanted it.
I know it is fashionable to say that if you just give the bullies what they want there will be peace but the problem is that what they really want is everything.
So no, FDR not giving them what they wanted did not start WWII.
Well, yes. Japan attempted to wipe out the Pacific Fleet because fuel wise they would only become weaker as time went on. I wear suspenders, that is how fashionable I am plus Goodwill turns me down when try to drop off my clothes.
Hitler decided to go to war with us, honoring the treaty he had with Japan, far as I know the only treaty he honored.
Aside from all that, I do not like the social policies FDR introduced into the US. Without FDR’s New Deal we would not have most, if not all, of the nutty social programs we have now. FDR was also a bully, he just put a nicer face on it.
On top of that, Eleanor was dog ass ugly.