Unpopular opinion: ranked choice voting will do little to solve the USA’s democracy issues.
For starters, there are plenty of countries that do use FPTP and still have plenty of third parties in their parliaments (Canada, UK, Taiwan, Australia off the top of my head). So FPTP does not inherently preclude third parties - rather, the USA simply doesn’t have any culture of multilateralism. I’d say this is mostly a byproduct of various cultural phenomena - the wealth gap, corporate media ownership, private campaign financing, win-or-lose mindset, etc.
But the greater issue is that RCV doesn’t really ensure proportionality. As long as you have a single winner from each district, there will be distortions between the proportion of parties for whom people vote and the ultimate parliamentary body. For example, even if you implemented RCV across the entire USA today, I’m pretty sure most legislative bodies would still be entirely dominated by a single party because of gerrymandering and single-member districts.
So if you want to fix the USA’s core issue, what you really need is a more proportional system - either have fewer, larger districts with multiple representatives from each one, or adopt something like MMP which is what Germany has (where you also cast a party vote to declare your preference for which party you most want represented in parliament and distribute proportionally along this tally across all voters). Not only does this make the final representation more fair, but it also does a much better job of making all votes matter, instead of only the lucky few in swing states or the rare competitive Congressional race.
But RCV on its own won’t do much. It is still a small improvement, and if you have the opportunity to adopt it, I say go for it. But at best, I think it would take decades, or maybe even generations, before it starts to improve things.
Also, while I know this doesn’t pertain quite so much to Presidential elections as the electoral college is used for, the USA is also fairly unique in that it has a directly elected head of government with much more power than other countries that also have a directly elected head of state. This is also a part of the problem - the executive branch is supposed to be the weakest of the 3 Federal branches - but it’s a discussion for another time.