I see RCV and STV used interchangeably. And the way I’ve seen RCV described in the US it is just STV with a better name for easier marketing. But I may be missing some subtlety. I also prefer MMP for parliamentary systems but changing the US to use MMP is several orders of magnitude harder than implementing RCV, which can be done state by state. It can even be implanted using multimember districts without changing anything. So it gives the US the best path to a better electoral system I think.