Averaged [CII] SB profiles obtained for our sample of 72 TNG50 galaxies at z = 4, 5, and 6 (solid lines), with shaded areas enclosing a 95% of different results obtained by different galaxy orientations. The different line colors represent the TNG50 profiles obtained assuming C⁺ abundances equal to the total C abundance (dark pink), C⁺ abundance obtained considering the UVB as incident field (light blue) and C⁺ abundance considering UVB and local young stars as ionization sources (orange). As a comparison, the black squares represent the results from the ALPINE survey.