Following the remarkable advances in the performance of metal halide perovskite solar cells, recent research efforts have focused more on enhancing their long-term stability. Among the various factors that impact the device's lifetime, humidity-driven degradation plays an important role and can significantly lower the device performance within hours. It is generally considered that humidity-induced degradation proceeds via the formation of hydrogen bonds between the water molecules and the nitrogen atoms in widely used ammonium-based organic cations like methylammonium (MA) and formamidinium (FA). To mitigate this process, it has been suggested that an interfacial passivation using sulfonium – rather than the ubiquitously used ammonium – cations may enhance the device stability against moisture. This work explores the impact of a dual interfacial modification by sulfonium- and sulfoxonium-based cations versus two commonly used ammonium-based ones. By examining the interfaces using optical spectroscopy and electron microscopy and evaluating the performance and stability of the devices, it is demonstrated that sulfonium- and sulfoxonium-based cations do not offer a significant advantage over ammonium-based cations, with the latter leading to enhanced stability only in certain cases.