Earlier quoted context omitted.
If gerrymandering persists, the dysfunction of Congress will also persist, no matter how many members there are. Representatives have no incentives to behave responsibly under the current districting situation.
One of the intended consequences of increasing the number of members is that each one is more easily replaced if they do not accurately represent the views of the constituents. My back of the envelope math gives the US 6400 member of the house at the current population which also has the effect of reducing each single member's importance.
By drawing district lines around politically homogenous populations, gerrymandering guarantees that representatives accurately represent the views of their constituents and enables hyper-partisan behavior without consequences. Adding representatives does nothing to change that. 6400 gerrymandered districts will give us the same results as 435.