Understanding the dynamics of small perturbations of extremal Kerr black holes requires a quantitative analysis of the interplay between the degeneration of the horizon red-shift effect—a stabilizing mechanism—and superradiance, which acts as a destabilizing mechanism. We present forthcoming results from a mathematically rigorous study of this interplay and its impact on precise late-time asymptotics (“late-time tails”) and instabilities for the charged scalar field equation on (near-)extremal Reissner–Nordström spacetimes. This model arises as the linearization of the Einstein–Maxwell–charged scalar field system. We further highlight key similarities and differences with the corresponding problem for the (uncharged) wave equation on (near-)extremal Kerr spacetimes.