It’s all a question of timing. If Hitler had delayed the invasion of Poland by two years....science, technology development, industrial growth....would have tipped to Japan and Germany by the early 1940s.
Possibly. But 1940 is when Penicillin was purified in the US. Which renders the soldiers of the US immune to most infections that stop all other armies dead in their tracks. And until Penicillin, illness is THE destroyer of all armies.
So, here we are. :)
At that time, the US had 30 cyclotrons, Germany had 2, Japan and UK each had 1. That is how dominant the US was in nuclear physics at the time.
...but the vast array of equipment and materiel he already had would have been rendered obsolete. When you go to war you have to use what you have.