  We perform explorative analyses of the 3D gluon content of the proton via a
study of (un)polarized twist-2 gluon TMDs, calculated in a spectator model for
the parent nucleon. Our approach encodes a flexible parametrization for the
spectator-mass density, suited to describe both moderate and small-$x$ effects.
All these prospective developments are relevant in the investigation of the
gluon dynamics inside nucleons and nuclei, which constitutes one of the major
goals of new-generation colliding machines, as the EIC, the HL-LHC and NICA.
