Molecular gas consumption timescales and SFEs. Upper-left panel: Depletion time as a function of (1 + z), shown in logarithmic scale. Sources are color-coded as follows: the z > 7 quasars are red (this work) and green (Venemans et al. 2017a, Novak et al. 2019, and Feruglio et al. 2023). Literature samples include: z < 4 star-forming galaxies (pink-shaded region; Tacconi et al. 2018); local Seyfert galaxies and quasars (red diamonds; Bischetti et al. 2019a, Shangguan et al. 2020, Salvestrini et al. 2020, 2022, and Salomé et al. 2023); quasars at Cosmic Noon (blue dots; Bischetti et al. 2021 and Bertola et al. 2024); and quasars at 6 ≲ z < 7 (gray circles; see Table C.1). The parameter space occupied by the simulated quasars from GAEA is shown as an orange-shaded region, with 10% isodensity lines. The dashed line represents the evolution of the depletion time with redshift (Sommovigo et al. 2022). Upper-right panel: SFE displayed as a function of L_IR. The best-fit lines are shown for illustration purposes only and were obtained from a linear fit of the data shown in the legend. Data points are color-coded as in the upper-left panel. Lower-left panel: SFE vs. L_bol. The black diamonds represent the median SFE value in each of the equally spaced L_bol bins. The vertical lines represent the distance between the 84th and 16th percentile of the SFE distribution in each bin. Data points are color-coded as in the upper-left panel. Lower-right panel: The histograms of the SFE distribution of each sample. The dashed line represents each distribution’s median value.