The idea that the bombs on Hiroshima and/or Nagasaki shortened the war in a significant way is in historic sciences at least contested.

I remember my professor at University arguing against the fact that this idea was presented as proven fact, when there were many question in the scientific community.

Not sure how maybe newer evidence might have changed it. I would need to dive into the actual scientific literature to update my knowledge of the topic.

The Operation Paperclip scientists helped build rockets for the post-war era. Not bombs.

The German / Austrian / Hungarian scientists that worked on the bomb came to the US years before the Manhattan project started.