Well, you are both correct, and mistaken. The “nothingness” as a Buddhist concept is more a mistranslation, because it is beyond concept by definition, and it is indeed something , just not a something that is anything. It is closer to the concept of O or Aleph in counting or math. It’s a placeholder for the non conceptual.

As for the other nothingness that you reference, it’s just pure abstraction and doesn’t exist by definition .