The forthcoming Habitable Worlds Observatory (HWO) and Great Observatories Maturation Program (GOMAP) promise unparalleled opportunities for probing emission and absorption lines from galaxies. This talk will focus on the use of hydrodynamical simulations for generating robust line modeling predictions essential for HWO endeavors. I will discuss the merits and challenges of various approaches, hindering a community consensus on galaxy formation. Given the complexities of comparing simulations with different physical accuracy, numerical resolution, and population statistics, I advocate for advancing the state-of-the-art across multiple methodologies, ranging from generic templates to comprehensive radiative transfer calculations. Finally, I will highlight several scientific questions that stand to gain from GOMAP capabilities, emphasizing the role of simulations in providing insights and interpretations.