I feel like we're trying to argue two different things.
You're arguing that the Nazi generals didn't develop a brand new type of warfare and they weren't tactical geniuses, which is a fair assessment.
I'm arguing that they may not have been geniuses, but they refined a single strategy that worked well on the European continent but fell apart when dealing with the USSR and extended operations in Africa. The Nazis also had a series of strategic blunders in attacking the UK as the lead Nazi military organization had no experience in strategic planning and it showed.
I feel like a lot of historical analysis gets pushed into extremes of all good and all bad decisions when there is a mix of decisions.