Redshift-dimming corrected X-ray SB profiles in the observed 0.5–2 keV band (SB_X) for the extended thermal emission around QSO ID1 (red circles), obtained using an energy conversion factor (ECF) of ≃4.6 × 10⁻¹¹ erg cm⁻² cnts⁻¹ based on the best-fit values of kT = 1.8 keV and Z/Z_⊙ = 0.014, and for the Spiderweb Galaxy (blue triangles) L24. A correction factor of 0.536 was applied to the Spiderweb hot halo’s SB_X profile from L24 to account for differences in the redshift-dependent intrinsic energy band. The black lines show the median (solid), 16th–84th percentile (dashed) and minimum-maximum (dotted) SB_X profiles of hot halos at z = 3 from the DIANOGA simulations, selected to have an average mass consistent with the estimated virial mass of the MQN01 halo (i.e. ∼3 × 10¹³ M_⊙).