> There is no such thing as trade imbalance

Well, hope i can educate you with some marx here ;)

https://en.m.wikipedia.org/wiki/Unequal_exchange

Marx theory of equivalence of exchange is the foundation with which he defines exploitation. With a universal comparison unit (value of labor), you can define unbalanced trades.

Dont ask me though, how a balanced trade would look like. Maybe we can only approximate it via outcome.