The cosmological constant problem reflects the enormous gap between naive quantum estimates of vacuum energy and the small but nonzero value inferred from observations. In earlier work we introduced phase-dependent models in which the vacuum spectrum is bounded by confinement at the QCD scale and suppressed at low energies. Building on that foundation, this paper presents the Quantum Energy Vacuum (QEV) model, where the spectrum is explicitly constrained by two natural cutoffs: QCD confinement in the ultraviolet and thermal suppression near \( T \approx 34\,K \) in the infrared. This dual mechanism reduces the zero-point energy by more than forty orders of magnitude and leaves a residual density which, under the influence of four physical components (entropic, thermal, hadronic, and Newtonian), is consistent with cosmological data. The QEV model reproduces the observed expansion history without a fundamental cosmological constant and explains flat galactic rotation curves through entropic, thermal, and hadronic contributions, without invoking dark matter halos. High-precision cosmological observations, including CMB measurements, Pantheon+ supernovae, and cosmic chronometers, provide the testing ground for this approach. Together, these results suggest that cosmic acceleration and galactic dynamics may both emerge from a bounded vacuum framework, pointing to the vacuum as an active and structured medium rather than a passive background.