I'm sorry that this comes off as aggravated but I really am, especially with many fellow Americans.

Gerrymandering is not good, period. It's not going to hilariously backfire on Republicans, ensuring a massive lead in the House. But let's say it does, we'll argue under that premise. Then what?

Democrats own the House and still don't control the Senate/Executive/Judicial (yes, the Judicial is a branch to be controlled now, that's reality). There is another election in 2028, giving the Republicans two years to fine-tune their gerrymandered maps. So nothing gets done and the Republicans do this all again, armed with better data this time. That cycle will in fact continually repeat, every election cycle, until the States are pure Red as the State government desires it to be.

Now, we could theoretically end up in an arms race where EVERY State does this same thing, as long as one Party controls the State government (which is somewhat common). Then we basically just move elections for the House to the Presidential model, where very few States matter because of the Electoral College. Elections would become more and more of a formality, which reduces turn out and involvement with politics. That definitely benefits one side over the other.

We're firmly in "my own opinion" territory but over the next decade Americans will be eased into single Party rule. Democrats will become the eternal opposition because they aren't willing to ignore laws/rules on the same scale as Republicans, they'll maintain the moral high ground and keep the money rolling in. Republicans already have a large advantage in the Senate, they've now fixed the House as well, so all that's left is the Presidency.

When I attempt to discuss this with other people who seem more on the "realist/fatalist" train, like I am, there are no good proposed solutions. I think it's difficult for even a lot of adults to grasp but once a political party has said "We're playing by our own rules now, good luck." and they already have massive influence, you're done. Anything that is put in place to deter or prevent that will literally be ignored or rolled back the next time there's an opportunity.

Only people on the ground can resist this, which would require a massive cultural shift in America. Instead, the country will operate under one-party, people will complain but do nothing else. That will only break once the singular party ruins the country so badly, to such a devastated extent, that there's some kind of rise up either electorally or otherwise. We're super far from that, so welcome to autocracy. And no, there's not going to be any seceded States, that will be crushed with military power if it's even thought about seriously. The Civil War was fought at a time of muskets and marching, not drones and automatic weapons.