Stellar mass–stellar velocity dispersion relations for simulated and observed galaxies in the different redshift bins. The dashed black line represents the median σ_★ for all TNG50 quiescent subhalos, while the solid black line corresponds to the Zahid et al. (2016) relation across all redshifts. All TNG50 subhalos are shown as gray dots, with the compact sample color-coded by their mass growth since z = 2 (except for the final bin, which is considered he starting point and is therefore left uncolored). Observational data are represented by diamonds, color-coded as follows: dark red for the extreme relics (e.g., extreme cases of group A for MaNGA, DoR > 0.7 for INSPIRE); red for relics (remaining group A of MaNGA and INSPIRE galaxies with 0.5 < DoR < 0.7); and blue for the non-relic group (classes B and C of MaNGA, DoR < 0.5 for INSPIRE).