In the early days of Barbarossa, a German general encountered a T-34 tank, and upon inspecting it, said, that if the Russians produced them on an assembly line, Germany would lose the war.
When Hitler met with the leader of Finland, Mannerheim...in an “open mike and video”, Hitler admitted to Mannerheim in a private conversation how shocked he was that the USSR had so many tanks.
Interesting video if you hadn’t seen this. It was discovered a few years ago (but hidden away for decades)
https://www.youtube.com/watch?v=oET1WaG5sFk