Azimuthally averaged power spectra of input and modeled (ψ_pix) perturbations for lens PS (computed within the same mask as in Fig. 5). Linear relations used to estimate the variance and slope β_GRF are overlayed (dashed lines), assuming the underlying perturbing field is a GRF (uncertainties are estimated from the least-squares fit). The crosses indicate the bin (2 × 10⁻¹) that is ignored for the linear fit, as it corresponds to the size of the mask.