My history teachers and textbooks always give me the impression that Nazi Germany was a great juggernaut and it took the combine forces of Soviet Union, the British and US to defeat it, without Allies the world will be speaking Germans, yes I have heard many great technological advancement in weaponry like StG 44 and V2 rockets but they came in quite late to the war. I have read a few history forums, stories and articles that argue Nazi Germany was not military strong, some citizens was unwilling to go for another war and overall not military ready for war. I heard in 1938, when Hitler wanted to go war for Czechoslovakia but his generals were ready to overthrown him because their military was not ready and the Germans manage to enjoy great success early on the war because luck and the France was ill prepare for war and not because of superior equipments and tactics the Germans have. Furthermore, I heard Germany's economy was actually on verge of collapses instead of being stable and almost back to normal as what the textbook said. How much of this is true?

I want to know as I recently I have discover the contents in my textbooks are a bit bias and oversimplify many world historical facts.