  In this work, we have studied the quasinormal mode, greybody factors, and
absorption cross section of de Sitter Reissner-Nordstr\"om black hole
surrounded by quintessence field in Rastall gravity. The violation of
energy-momentum conservation has a non-linear effect on the quasinormal modes.
With an increase in the black hole charge, both real parts of quasinormal modes
i.e. oscillation frequency of ring-down Gravitational Waves (GWs) and damping
or decay rate of GWs increase non-linearly. A similar observation is made for
the black hole structural parameter also, however in this case the variation is
almost linear. The remnant mass of a black hole depends on different physical
parameters of a black hole. In the case of greybody factors also, we observed
that both parameters have similar impacts. With an increase in these
parameters, greybody factors decrease. Moreover, the null geodesics and the
impact of Rastall gravity on the light trajectory are also investigated. Our
study suggests that the presence of a surrounding quintessence field may shadow
the existence of black hole charges in such black hole configurations.
