  The interplay between charge transfer and electronic disorder in
transition-metal dichalcogenide multilayers gives rise to superconductive
coupling driven by proximity enhancement, tunneling and superconducting
fluctuations, of a yet unwieldy variety. Artificial spacer layers introduced
with atomic precision change the density of states by charge transfer. Here, we
tune the superconductive coupling between NbSe$_2$ monolayers from
proximity-enhanced to tunneling-dominated. We correlate normal and
superconducting properties in [(SnSe)$_{1+{\delta}}$]$_m$[NbSe$_2$]$_1$
tailored multilayers with varying SnSe layer thickness. From high-field
magnetotransport the critical fields yield Ginzburg-Landau coherence lengths
with an increase of 140 % cross-plane , trending towards two-dimensional
superconductivity for m > 9. We show cross-over between three regimes: metallic
with proximity-enhanced coupling, disordered-metallic with intermediate
coupling and insulating with Josephson tunneling. Our results demonstrate that
stacking metal mono- and dichalcogenides allows to convert a
metal/superconductor into an insulator/superconductor system, prospecting the
control of two-dimensional superconductivity in embedded layers.
