Redshift evolution of DM contributions as a function of large-scale structure. Left panel: mean, median, and standard deviation around the mean of the DM–redshift relationship for TNG300-1 halos (; yellow), filaments (; cyan), and voids (; purple) derived using our metric. These are compared to the ⟨DM_cosmic⟩ subcomponents (see Sect. 6.1): ⟨DM_IGM⟩ (dashed black line) and ⟨DM_CGM⟩ (dot-dashed black line). Right panel: means (coloured lines) and standard deviations (shaded regions) of the equivalent fractional DM contributions ⟨f_DM⟩ accumulated due to traversing each type of structure by our FRBs originating at given redshifts.