Ranked choice would absolutely still help. The two party state is utterly awful. And while primaries exist and people should use them, let's be honest: most people won't. We need it to be easier to vote for who people like. Primaries aren't that, since they're an extra vote you have to be aware of and take the time to research and vote for.
As an aside, ranked voting isn't what I'd consider ideal for the general election, either. It's still heavily disproportionate. Proportional voting is far superior for ensuring representation. Eg, suppose 25% of the population likes progressives, 50% likes centrists, and 25% like conservatives. Any form of single winner ballot (ranked choice or FPTP) is gonna favour the centrist, even though that means 50% of the population don't get their ideal representation.