  In this study, we investigate the role of bulk viscosity in $f(Q,T)$ gravity
in explaining late-time cosmic acceleration. This model, an extension of
symmetric teleparallel gravity, introduces viscosity into cosmic matter
dynamics for a more realistic representation. Specifically, we consider the
linear form of $f (Q, T) =\alpha Q + \beta T$, where $\alpha$ and $\beta$ are
free model parameters. To assess the model, we derive its exact solution and
use Hubble parameter $H(z)$ data and Pantheon + SNe Ia data for parameter
estimation. We employ the $\chi^2$ minimization technique alongside the MCMC
random sampling method to determine the best-fit parameters. Then, we analyze
the behavior of key cosmological parameters, including the deceleration
parameter, bulk viscous matter-dominated universe density, effective pressure,
and the effective EoS parameter, accounting for the viscous type fluid. We
observe a transition in the deceleration parameter from a positive
(decelerating) to a negative (accelerating) phase at transition redshift $z_t$.
The matter density shows the expected positive behavior, while the pressure,
influenced by viscosity, exhibits negative behavior, indicative of accelerating
expansion. Furthermore, we investigate the energy conditions and find that
while the NEC and DEC meet positivity criteria, the SEC is violated in the
present and future epochs. The $Om(z)$ diagnostic suggests that our model
aligns with quintessence behavior. Finally, our $f(Q,T)$ cosmological model,
incorporating bulk viscosity effects, provides a compelling explanation for
late-time cosmic behavior, consistent with observational data.
