[OI] 145μm luminosity and [OI] 145μm/[CII] 158μm ratio as a function of SFR for our model galaxies at z = 6. Different colors refer to different model assumptions in the post-processing pipeline with DESPOTIC. The red one represents the fiducial model adopted in this work, the cyan is a model where the CRs rate is scaled with the SFR density, the yellow and purple are models where the density profile is assumed to be logotropic and power-law. Solid lines refer to median trends and shaded regions indicate the 16th to 84th percentile dispersion. For reference, the available z ≳ 5 observations discussed in this work are also reported, with the same symbols as in Figs. 6 and 7.