Maps of the simulated eROSITA detection efficiency ξ for QPE sources in a 2D grid of average peak luminosity () and average recurrence time (⟨t_recur⟩), for the case of z = 0.02 (top) and z = 0.05 (bottom). Squares with a red contour highlight the known QPE sources in the respective redshift bins. Apart from the grid points around the periods resonating with eROSITA’s 4 h cadence, ξ is fairly homogeneous above the cut provided by the sensitivity of each redshift bin.