  The Dresden-II reactor experiment has recently reported a suggestive evidence
for the observation of coherent elastic neutrino-nucleus scattering, using a
germanium detector. Given the low recoil energy threshold, these data are
particularly interesting for a low-energy determination of the weak mixing
angle and for the study of new physics leading to spectral distortions at low
momentum transfer. Using two hypotheses for the quenching factor, we study the
impact of the data on: (i) The weak mixing angle at a renormalization scale of
$\sim 10\,\text{MeV}$, (ii) neutrino generalized interactions with light
mediators, (iii) the sterile neutrino dipole portal. The results for the weak
mixing angle show a strong dependence on the quenching factor choice. Although
still with large uncertainties, the Dresden-II data provide for the first time
a determination of $\sin^2\theta_W$ at such scale using coherent elastic
neutrino-nucleus scattering data. Tight upper limits are placed on the light
vector, scalar and tensor mediator scenarios. Kinematic constraints implied by
the reactor anti-neutrino flux and the ionization energy threshold allow the
sterile neutrino dipole portal to produce up-scattering events with sterile
neutrino masses up to $\sim 8\,$MeV. In this context, we find that limits are
also sensitive to the quenching factor choice, but in both cases competitive
with those derived from XENON1T data and more stringent that those derived with
COHERENT data, in the same sterile neutrino mass range.
