  In this work, we delve to investigate a feasible range of dark matter (DM)
masses within a non-supersymmetric $SO(10)$ Grand Unified Theory (GUT) scalar
dark matter model, in freeze-out scenario. This model includes a singlet scalar
denoted as S and an inert doublet represented by $\phi$. Being part of SO(10),
the quantum numbers of DM particles are assigned and hence we know their
nature. These fields are odd under a discrete $Z_2$ matter parity
$(-1)^{3(B-L)}$. The dark matter with mass 300 $\leq M_{DM} \leq$ 1000 GeV
emerges as a mixture of the $Z_2$-odd scalar singlet $S$ and the neutral
element of the doublet $\phi$, both residing within a \textbf{16}-dim scalar
representation of $SO(10)$. In this work we consider a real scalar \textbf{S}
belonging to \textbf{16} of SO(10) as DM. We also investigate the one-loop
vacuum stability through the solution of Renormalization Group Equations (RGEs)
for the model's parameters. Subsequently, we scrutinize the model's predictions
within the confines of contemporary theoretical and experimental restrictions.
In addition to achieving vacuum stability in the SO(10) framework, the DM mass
is found to lie in the previously unaddressed (theoretically) intermediate mass
region of 300$\leqslant$ MDM $\leqslant$ 1000 GeV which also adheres to many
current phenomenological constraints, like recent direct experimental bounds
from XENON1T, indirect detection bounds from Fermi-LAT experiment, Higgs
invisible decay and Electroweak Precision Test. The stability of the
electroweak vacuum is seen to be present up to the Planck scale. These model
predictions possess the potential for future validation through dark matter
search experiments, as they are testable in future DM search experiments, along
with the added feature that the model is a part of an elegant grand unified
theory.
