If a third party ever truly gained traction on the national stage, what makes you think they won't be bought by the billionaire class? Musk basically bought the government purse strings for less than $300 million. That's pocket change for the truly wealthy.
American society is in crisis and this crisis will likely continue to grow economically as well as due to larger effects on the horizon such as global warming. From a practical standpoint if we are serious about unseating the power of the billionaire class (which is highly realistic as society continues to self-destruct over the long horizon) things like ranked choice voting should serve as tactical goals in a broader struggle for democratic process in our country. But yes it would be naive to consider ranked choice voting to be enough on its own to unseat them.
RCV is a weakass attempt to move us in the direction of the Westminster system without actually just fixing the system. You want Westminster just go there and don't fuck around half-assing it with RCV.