Expected error ellipses of cosmological parameters from the analysis of AGNs and galaxy clusters in the complete eROSITA all-sky survey. Photometric redshift quality σ₀ = 0.03, 0.005 and f_fail = 0.1, 0.01 for AGNs and clusters, respectively. Prior 0.1 on h is added to the Fisher matrix. The corner plot shows the results derived from the Fisher matrix of clusters (blue), AGNs (orange), and combined (green) samples. The table shows the percentage errors on the parameters and the value for the FoM.