In this talk, we will explore the dual role of neutrinos in direct detection experiments. We will demonstrate how solar neutrinos hinder the search for sub-GeV dark matter through DM-electron scattering. Specifically, we will show that, for DM-electron scattering mediated by heavy particles, solar neutrinos can pose a significant background in certain well-motivated regions of parameter space. Conversely, we will highlight how neutrino events at XENONnT and PandaX-4T are probing the Standard Model's weak mixing angle in complementary regions—remarkably, at the lowest energy scale to date.