A voting system which leads to more proportional outcomes is probably the correct solution here, but there is a "hack" which could fix gerrymandering specifical

A voting system which leads to more proportional outcomes is probably the correct solution here, but there is a "hack" which could fix gerrymandering specifically (if implemented) without changing the ballots, the size of districts, or the counting process. The idea is to look, after an election, at the proportion of seats won by each party, and the proportion of votes won (in aggregate) by each party, and ask "Could these two sets of proportions be brought more into line by appointing a different winner in one of the districts?". If a change to some winner could improve the proportionality, then a rule would say that this change to the results should be imposed (on the district where the losing party came closest to winning). Of course, overriding the true result in a district would be hugely controversial, but the idea is that the rule would act as a deterrent and never need to be invoked, because the districts would be drawn in a proportional way to begin with.