Yeah. It sounds cliche, but "listen with your heart" is really accurate. She's saying she misses the old days when America worked. That's not wrong (I mean for white people it's not, I would recommend not to go down that rabbit hole lol). A lot of it isn't about what you say to her, it's how you say it. If everything you say sounds cold and factual and correcting her, of course she's not going to want to listen and it's just going to be a hostile interaction.
It is tough. My experience with stuff like this is that they just live in a whole different reality, so it is hard to get a foothold. I had to work really hard at having conversations with people for whom the tone of voice and emotional intent is a huge part of how they process the information (which I think is most people). That's not how I operate, so it was hard to keep it in mind without coming off as fake or condescending, but if you're genuine about what you mean and focus on sort of the core of why you came to your beliefs (not the facts but the reasons why you care about the facts so much), a lot of times it comes across better. And then on top of that, you're dealing with someone where their factual understanding of the world is off in la-la land, so it's hard to not just lecture them or tell them what's what.
Like that kind of thing about Reagan, my first reaction to the answer is "Yeah, and have you wondered why that hasn't ever happened since then? Why everyone was doing okay until the late 80s and then it all went to hell and hasn't come back? Honestly that's what I want, is to get back to when working people had a fair shake and people could make a living. Don't you want that? It sure as hell is not happening now under Trump..."
But again, it's not the words, it's the intent behind them. If you're reasonable and you care, then it's hard for her to take your statements hostile even if she doesn't agree with them (honestly I can guarantee you that one conversation or even several about it will not change her mind.) But you can sort of plant seeds and then she'll come around on her own, or if she does not then oh well.
If she is being overtly hateful on her own then it's different. IDK what you can even do then. But mostly in my experience it is people who are so twisted up that they think the Democrats are so hateful that of course things X, Y, and Z make perfect sense and are the only humane thing to do. Mostly.

Yeah, because everything was fine and everyone got soft and complacent.
Like it or not, we're coming to the end of that, we've not even scratched the surface of how bad it's actually going to get. The people and communities that smarten up will (sometimes) survive, and more and more, the ones that do not will not.