Left panel: α_ox vs. log L_UV for our high-λ_Edd AGN (blue triangles) compared to the XMM-COSMOS type-1 AGN (light grey crosses) of Lusso et al. (2010). The solid black line is the best-fit relation from the same authors. Dashed black lines describe the 1σ spread of the above relation. The solid blue line is the best-fit relation obtained from Martocchia et al. (2017). Green squares and red circles indicate the sub- and super-Eddington AGN from Liu et al. (2021), respectively. Purple diamonds are the 13 WISSH QSOs from Zappacosta et al. (2020). The red solid line marks the reference value for X-ray weakness, i.e. Δα_ox ≤ −0.3 (Pu et al. 2020). Right panel: distribution of the same sources described in the adjacent panel, divided into different regimes of bolometric luminosity, in the α_ox − log λ_Edd plane. For the XMM-COSMOS AGN sample, only those sources with available measurement of λ_Edd are included. The solid black line indicates the best-fit relation from Lusso et al. (2010). Dashed black lines describe the 1σ spread of the above relation. The shaded interval at log λ_Edd ∼ 0 is included to highlight that AGN with very similar values of λ_Edd can show a widespread distribution in α_ox due to their different L_bol.