AB magnitude in Rubini filter at ∼12 hours post-merger as a function of redshift for KNe and on-axis (θ_view < 15°) GRB afterglows following BNS detected by ET as a stand-alone observatory (left panels) and in a network with CE (right panels). The few bright KNe (m_AB < 21) in the upper-right panel are not visible due to their low density relative to the bulk of the population, which dominates the color scale. The cross, upwards pointing triangle, and star respectively represent AT2017gfo, and the optical counterparts of GRB 211211A (Rastinejad et al. 2022) and GRB 230307A (Levan et al. 2024), two GRBs followed by a KN, at ∼12 hours after the GRB prompt detection. A Gaussian filter was applied to the data in the top panels and bottom-right one for visualisation purposes.