Sridhara Maharaja has stated ,as others have,
that Shiva is the state of consciouness
that is freedom from all material contaminations
and misconceptions, the highest state of consciousness
in this world.

In the brahma samhita, shiva is described in relation
to krishna as milk is to yogurt.

in the material world shiva does the work of krishna.

Shakti in the context you used ,i assume refers to Durga,
who is the expansion of Lakshmi, who is the expansion
of Radha.

she is also Shiva's consort.