  In this work, the sensitivity of future germanium-based reactor neutrino
experiments to the weak mixing angle $\sin^{2}\theta_{W}$, and to the presence
of new light vector bosons is investigated. By taking into account key
experimental features with their uncertainties and the application of a
data-driven and state-of-the-art reactor antineutrino spectrum, the impact of
detection threshold and experimental exposure is assessed in detail for an
experiment relying on germanium semiconductor detectors. With the established
analysis framework, the precision on the Weinberg angle, and capability of
probing the parameter space of a universally coupled mediator model, as well as
a U(1)$_{\rm B-L}$-symmetric model are quantified. Our investigation finds the
next-generation of germanium-based reactor neutrino experiments in good shape
to determine the Weinberg angle $\sin^{2}\theta_{W}$ with $<10$\% precision
using the low-energetic neutrino channel of CE$\nu$NS. In addition, the current
limits on new light vector bosons determined by reactor experiments can be
lowered by about an order of magnitude via the combination of both CE$\nu$NS
and E$\nu$eS. Consequently, our findings provide strong phenomenological
support for future experimental endeavours close to a reactor site.
