I completely get your frustration and believe that your arguments make sense to a degree. The problem for the older voters is the dominance of Reagan and his legacy from1980 to 2020.
Reagan won every state but Minnesota in 1984. His ideas and ideology have towered over the country in the generation since he was elected. His formula of cutting taxes, decreasing regulation, and strengthening the military has a powerful hold over the imagination of older Americans. They also believe he won the Cold War.
LBJ was the last liberal president until Barack Obama. Carter was a Conservative Democrat and Clinton was a pragmatic centrist. Clinton never won the popular vote and arguably only won because of Ross Perot. Obama and Clinton took the views that did because that was the only way they could win voters and the elections. Each of them got crushed in the midterm elections following their victory.
Politics is about principles but, it is also about power. Mitch McConnell has done a brilliant job of consolidating conservative power in the Senate and the courts. In doing so he has repeatedly laid bare the hypocrisy of the Republican party. They will make up precedents and then drop them as soon as they are inconvenient.
I'm sure the Democrats will try to pack the Supreme Court as soon as they get the chance. That did not work out well for FDR, and he was the best politician of the twentieth century in the United States.
It seems like we have three basic choices. Pray that things will somehow return to some semblance of constitutional normalcy, give up and divide into six or seven separate countries. Or significantly modify the Constitution so that the government reflects the will of the governed. None of them appears to be a plausible solution at present.
I will caution you that "fighting bare-knuckled to save the world" may just provide Trump with the pretext to impose martial law in the cities. The people who have achieved the most durable change have done it nonviolently. It may seem like a fool's errand, but it may be the only chance we have to save the world.