 If explanatory fundamentality and compositional fundamentality are genuinely two different notions corresponding to two independent notions of fundamentality, then  (RI)  does allow the overlap of explanatory and compositional fundamentality. But there could certainly be other considerations that count against this. For instance, if (RI) is understood to mean that to be fundamental is just to be at the termination point of some dependence relation, then the debate between monism and pluralism could just be a debate about the direction of compositional fundamentality, where compositional fundamentality terminates in the mereological atoms and its converse terminates in the whole cosmos. In other words, this could be understood as a debate about whether explanatory fundamentality aligns with compositional fundamentality or its converse. Whichever way we go here, we would seem to end up aligning some notions of fundamentality and misaligning others.