  We update the dust model present within the Simba galaxy simulations with a
self-consistent framework for the co-evolution of dust and molecular hydrogen
populations in the interstellar medium, and use this to explore $z \geq 6$
galaxy evolution. In addition to tracking the evolution of dust and molecular
hydrogen abundances, our model fully integrates these species into the Simba
simulation, explicitly modelling their impact on physical processes such as
star formation and cooling through the inclusion of a novel two-phase sub-grid
model for interstellar gas. In running two high-resolution simulations down to
$z \sim 6$ we find that our Simba-EoR model displays a generally tighter
concordance with observational data than fiducial Simba. Additionally we
observe that our Simba-EoR models increase star formation activity at early
epochs, producing larger dust-to-gas ratios consequently. Finally, we discover
a significant population of hot dust at $\sim 100$ K, aligning with
contemporaneous observations of high-redshift dusty galaxies, alongside the
large $\sim 20$ K population typically identified.
