  Recently, there has been a surge of interest in the 4D Einstein-Gauss-Bonnet
(4D EGB) gravity theory which bypasses the Lovelock theorem and avoids
Ostrogradsky's instability. Such a novel theory has nontrivial dynamics and
presents several predictions for cosmology and black hole physics. Motivated by
recent astrophysical observations and the importance of anti-de Sitter
spacetime, we investigate shadow geometrical shapes and deflection angle of
light from the charged AdS black holes in 4D EGB gravity theory. We explore the
shadow behaviors and photon sphere around such black holes, and inspect the
effect of different parameters on them. Then, we present a study regarding the
energy emission rate of such black holes and analyze the significant role of
the Gauss-Bonnet (GB) coupling constant in the radiation process. Then, we
perform a discussion of holographic heat engines of charged 4D EGB-AdS black
holes by obtaining the efficiency of a rectangular engine cycle. Finally, by
comparing heat engine efficiency with the Carnot efficiency, we indicate that
the ratio $\frac{\eta }{\eta_{c}}$ is always less than one which is consistent
with the thermodynamic second law.
