A two party system is an inescapable consequence of the plurality voting system (aka first-past-the-post voting) which is the system used by nearly all states and districts in the US, and much of the rest of the world. To fix the two party problem, the first step is to change the voting system. There are a number of alternative voting systems, each with their own pros and cons and situational uses. For legislative bodies, boards, or any other elected committee, I'm partial to proportional voting. And for single seat elections, I think approval voting is the ideal.
The thing that makes approval voting and other single seat voting systems better than plurality is that you vote for everyone you like. The way that that vote is cast and counted differs between systems. But in all cases, the benefit, ideally, is when 3 or more candidates exist for a seat, it prevents the least popular candidate from winning just because the other more popular candidates split the opposing voters. If you vote for each candidate you like, the candidates are never splitting the votes. The funny thing to me about most of these other fairer voting systems is that, while they are susceptible to a sort of spoiler effect from overly strategic or cynical voters who will simply only support one candidate, the result of that is just plurality voting, which we already have now. In other words, our current system is the worst case scenario for other, better, voting systems.
plurality voting system (aka first-past-the-post voting) which is the system used by... much of the rest of the world
Is this accurate? My understanding is that at least in Europe, it is only the UK and Belarus that use first-past-the-post; everywhere else uses some form of proportional voting.
It's not the majority of the world, but there are a few dozen countries that primarily use FPTP. It's used in North America, Europe, Africa, South Asia, the Middle East and a bunch of Pacific island nations. Belarus and the UK appear to be the only European nations to do so though, yes.
State election reforms to ranked choice voting have already started some places. Alaska, Hawaii and Maine all use it for some state elections. Some other states use it in some local jurisdictions. Of course, several backwards states have outlawed Ranked Choice altogether. Once it's used widely enough and been demonstrated to work well, that makes it easier to get it on a ballot at the federal level.
What can you do personally? Advocate for it where relevant, contact your representatives and let them know it's important to you, and vote for it if given the chance.