TNG300 lightcone (LC-TNGX) built in Shreeram et al. (2025b) overplotted with the filaments, which are identified using the DisPerSe algorithm (Sect. ). The top panel shows the central galaxies in LC-TNGX that are classified into five distinct large-scale environments categories: (1) clusters in blue, (2) cluster outskirts in orange, (3) filaments in green, (4) filament-void transition region in red, and (5) voids and walls in purple, as defined in Sect. 2.3. The bottom panel zooms in on the lightcone, showing the X-ray events generated with pyXsim in the 0.5 − 2.0 keV energy band with the filaments depicted by the yellow-dashed lines. While the filaments are identified using the galaxy distribution, we show that the hot gas emitting X-ray events trace the cosmic web. This alignment validates the full pipeline used in this work, from the lightcone construction and X-ray map generation to filament identification.