The JWST has uncovered a large population of UV-bright galaxies at redshifts above ~10, which surpasses the predictions from a range of theoretical models developed based on lower redshift galaxies. While various solutions have been proposed focusing on systematically increasing the UV photon yield in high-redshift galaxies, I will discuss in this talk an alternate solution from UV variability. The Eddington bias drives a strong enhancement of the bright end UVLF in the presence of large scatters in UV luminosities of galaxies, and can reconcile canonical galaxy formation models with JWST constraints. Such UV variability, stemming mainly from bursty star formation, is evident in high-resolution cosmological simulations that resolves the multiphase interstellar medium (ISM), e.g. the FIRE simulations. I will conclude my talk by introducing a forthcoming simulation suite, THESAN-ZOOM, which bridges radiative transfer method for the large-scale reionization and the explicit modeling of star formation/feedback/dust enrichment below the ISM scale.