Abstract: JWST has revealed a remarkably diverse population of high-redshift galaxies, reshaping our understanding of early galaxy formation. However, interpreting these spectral data presents a fundamental theoretical challenge. In this talk, I will first highlight key early JWST results and the limitations of existing models in extracting physical properties from spectra. I will then introduce a new suite of simulations that incorporate non-equilibrium primordial, metal, and molecular chemistry alongside on-the-fly radiation transfer. These next-generation models enable first-principles forward modeling of JWST observations, offering new insights into the physical processes governing the formation and evolution of the first galaxies.