But yes, the route to avoiding a second US Civil War is only incidentally through the “eliminating gerrymandering” nodes of the graph—the 50/50 saturation of the vote into two spineless political parties happens in both the House (gerrymandered to hell) and the Senate (not gerrymandered at all) and is a consequence of something more fundamental. States do need to switch to the proportional system, but there is a decent chance that the Supreme Court might destroy this out-of-hand, in which case a Constitutional amendment may well be necessary.
[1] “Would Switching to a Proportionate House Require a Constitutional Amendment?” https://politics.stackexchange.com/questions/42551/would-swi...
Geography will always play into it, especially in our odd hybrid system where we insist on devolving many laws to the states (such that even obvious crimes like murder, and apparently-unrelated notions like real estate or health care, end up with 50 separate laws with small but crucial differences). But there are lots of ways to change the system so that you're not solely linked by geography and hoping that, if you're in a local minority, somebody else will elect somebody to represent your view.
There are a few ways you can do this, Jefferson developed one of them so that's got a nice pedigree. It is also a good way for any third party to start to get some attention. Getting 20% of votes together to have your candidate as the fifth member for a district with 2 Dems and 2 Republicans is going to be easier than finding a plurality of voters for a single rep when the two big parties are both saying that's a wasted vote.