Wernher von Braun didn't have a rival/opponent nation he could betray America to.

Qian Xuesen did and did.

Did you forget that most of his colleagues worked with the USSR? Von Braun was just lucky that the US got to him and captured him first.

Von Braun was not "just lucky" to get captured by the US. He and his immediate staff took active steps to get captured by the Americans [1].

[1] https://en.wikipedia.org/wiki/Wernher_von_Braun#Surrender_to...

Dumb comment. Nazis were blood enemies of communists. They didn’t want to fight the Americans or even the British.