We have something here that has "worked", perhaps "survived" is a better word, for 246 years. It's ugly, it's messy, the way the sausage gets made is bloody, and sometimes it is ineffective at addressing issues quickly, but it does seem to get there eventually. It is the worst form of government on the earth - except for all the rest. We need to be careful about throwing the baby out with the bathwater.
The hyper-partisanship is nothing new. I am often amazed at reading what some congressman said in the 1850's or 60's about their political opponents - things no one would say today. I look at our two-party system and see the good in it - the moderating influence it has. Law is hard to make because our founders specifically wanted to avoid tyranny of the majority, thus we got checks and balances, a constitution that law has to fit into, a legislative chamber based on population that is prone to passions and political turbulence, and one that is based on 2 representatives per state that has a more calm and deliberate tone (usually) and generally must bring some from the other side to advance a law.
Parties don't necessarily seek the good of the country, but rather what benefits them, but because of the constitutional structure of government, those kinds of things get attenuated. The "gridlock" is a good thing imo. Each new law necessarily takes a bit of freedom away from someone. So, the less congress does, the better in most cases. When something has to be done, the parties seem to find a way to work it out eventually.
Acknowledging my bias and how the following reflects that bias, I think the change we have seen in the last decade or so is a shift toward conservatism and away from establishment Republicanism in the one party and a significant lurch to the left in the other party. Both have been reactionary toward the other. My bias aside, I think conservatism is a reasonable, not a radical, place for an American party to politic and govern from. I do not think the cultural Marxism, anarchy, and economic socialism of the left is reasonable, but rather radical - and it is what is driving most of our current dysfunction. Trump accelerated the reactionary radicalism of the Dems because of the visceral hatred they had for him and he fed that by constantly poking them in the eye.
Politics has a wonderful way of forcing correction on parties. When you get your brains beat in with an election, it normally causes a party to reevaluate their policy positions and messaging. The Dems should have done that in 2016, but they went the "Russia, Russia, Russia" route and those chickens are going to come home to roost this fall. Until they have their come to Jesus moment, the Dems will not recalibrate and reconfigure, and will continue to bleed voters. Wise heads on that side of the aisle need to reign in the more radical elements of their tent and certainly stop following their policy ideas - that include ideas that seek to change the rules of the game to help them win. Center-left ideas have won before and will win again. Get back to that, run solid, common sense candidates that are good communicators, and they will win in a lot of places. But continuing the drift toward being the Amercian hammer and sickle party will make them a minority for decades.