Quantum resource theories identify resourceful states by their separation from a set of free states, but a general state-level operational meaning for this separation is often missing. We introduce bounded witness-based monotones for resource theories with closed free sets and show that they quantify an activation potential for standard two-qubit correlations. For closed convex free sets, the monotones are faithful, convex, Lipschitz continuous, and strongly monotonic under free instruments. For closed nonconvex free sets, where single-copy witnesses cannot distinguish the free set from its convex hull, faithfulness is restored by a natural two-copy lift. For witnesses normalized to the unit box, the resulting quantities are exactly proportional to the maximal entanglement or Einstein-Podolsky-Rosen steering generated by explicit witness-dependent measure-and-prepare channels whose outputs are Werner states. Applied to continuous-variable systems, the construction unifies Wigner negativity, genuine non-Gaussianity, and standard non-Gaussianity. Further, the measure is illustrated by evaluation through several examples inspired from quantum optics.