marmara sea

Is it possible for Nicomedia, with dedication from whoever controls it, to surpass Byzantium/Constantinople as the major Marmara Sea port? Would this require a PoD before or during Constantine's reign? What sort of advantages did Nicomedia have, compared to Byzantium?

This is one question that has been plaguing my head for quite a while. Suppose that the Marmara area which connects Europe to Asia Minor is uninhabited, and you are tasked with choosing the capital of a state centered in this location. The question is, which of these two straits is more feasible...