Evolution of the rms of the RM with redshift in IllustrisTNG for six different overdensities in decreasing order from top to bottom (dashed lines). The measurements of the rms of the RRM derived from the LOFAR data (Carretti et al. 2023) based on the GRM model of Hutschenreuter et al. (2022) are shown in individual redshift bins (orange data points) with a power-law fit (orange line) and a constant $\sqrt{⟨{\mathrm{RRM}}^2⟩}$ fit (horizontal red band). The blue data points show the rms of the RRM calculated using the GRM model of Hutschenreuter & Enßlin (2020), namely GRM2020.