  We here propose a mechanism that predicts, at early times, both baryon
asymmetry and dark matter origin and that recovers the spontaneous baryogenesis
during the reheating. Working with $U(1)$-invariant quark $Q$ and lepton $L$
effective fields, with an interacting term that couples the evolution of
Universe's environment field $\psi$, we require a spontaneous symmetry breaking
and get a pseudo Nambu-Goldstone boson $\theta$. The pseudo Nambu-Goldstone
boson speeds the Universe up during inflation, playing the role of inflaton,
enabling baryogenesis to occur. Thus, in a quasi-static approximation over
$\psi$, we impressively find both baryon and dark matter quasi-particle
production rates, unifying \emph{de facto} the two scenarios. Moreover, we
outline particle mixing and demonstrate dark matter takes over baryons.
Presupposing that $\theta$ field energy density dominates as baryogenesis stops
and employing recent limits on reheating temperature, we get numerical bounds
over dark matter constituent, showing that the most likely dark matter boson
would be consistent with MeV-scale mass candidates. Finally, we briefly
underline our predictions are suitable to explain the the low-energy electron
recoil event excess between $1$ and $7$~keV found by the \texttt{XENON1T}
collaboration.
