RCV will do nothing to break the duopoly in America. RCV will basically allow you to vote for the Democrats or Republicans without bubbling their name on your ballot.
Contrary to what is stated, RCV falls apart as soon as more than 2 parties become viable. It suffers from the spoiler effect.
RCV, like plurality voting, only reflects your preference for one candidate at a time. In fact, it's relatively accurate to say that RCV is just plurality with (literally) extra steps (rounds).
One of the better ballot changes we can make is to move to something like STAR voting, which can capture the nuance of magnitude of preference for ALL candidates at once.
However, changing voting method alone is not enough. Proportional representation and expanding the number of elected officials are two powerful ways to introduce new ideas and break up power structures.
And, of course, campaign finance reform such as democracy vouchers
RCV is a rebrand of the voting method IRV, which was used by many cities in the early 20th century. Due to inconsistent results, it was repealed. So, unfortunately, conservatives have a leg to stand on when they attack RCV.
For clarity: their specific attacks take things to the extreme and often have some racist underpinnings, but there is a kernel of truth to attacking specifically on the method itself.
That is why I support something like STAR voting, it doesn't suffer from many of RCV's issues
I wish your ballot measure luck however, because at the end of the day it still is, mildly better than FPTP