The Evaporating Universe II: Structure Formation with Dark Matter Evaporation ABSTRACT: We apply the Evaporating Universe (EU) framework to structure formation, demonstrating resolution of the S8 tension and small-scale structure problems. KEY RESULTS: - S8 tension reduced from 3.2σ (ΛCDM) to 1.2σ (EU) - Core-Cusp: 99.5% central density reduction via SIDM - Too-Big-to-Fail: 55% Vmax reduction - JWST early galaxies: 1.5× faster collapse, 45% SF boost - Neutrino mass: Σmν = 0.06 eV (matches oscillation minimum) - DESI BAO: Δχ² = +6.0 improvement over ΛCDM PARAMETERS: - epsilon = 0.0598 (Yukawa coupling) - lambda = 0.6581 - w0 = -0.98 (quintessence) - H0 = 71.3 km/s/Mpc, Ωm = 0.319 Related: Paper I (DOI 10.5281/zenodo.18181063) Keywords: S8 tension, structure formation, dark matter, SIDM, JWST