>it’s why one of the Nazi symbols is that black cross as this is what the Teutonics wore

That's completely false. While it's true that Iron Cross is a reference to the Teutonic Knights it did not originate with the Nazis, it's a Prussian medal that dates back to the Napoleonic Wars. They used it because Prussia has its origins in the Order.

The Nazis used it because it's a German military symbol, but it is not associated with the Nazis in Germany (although it is in the West), it's still the symbol of the German Armed Forces and they still use it to this day on vehicles (here it is on a tankand here it is on an helicopter).