  In recent years, a growing number of regularly rotating galaxy discs have
been found at z $\geq$ 4. Such systems provide us with the unique opportunity
to study the properties of dark matter halos at these early epochs, the
turbulence within the interstellar medium and the evolution of scaling
relations. Here, we investigate the dynamics of four gas discs in galaxies at
\textit{z} $\sim$ 4.5 observed with ALMA in the [CII] 158 $\mu$m fine-structure
line. We aim to derive the structural properties of the gas, stars and dark
matter halos of the galaxies and to study the mechanisms driving the turbulence
in high-\textit{z} discs. We decompose the rotation curves into baryonic and
dark matter components within the extent of the [CII] discs, i.e. 3 to 5 kpc.
Furthermore, we use the gas velocity dispersion profiles as a diagnostic tool
for the mechanisms driving the turbulence in the discs. We obtain total
stellar, gas and dark matter masses in the ranges of $\log{(M/M_{\odot})} =
10.3 - 11.0$, $9.8 - 11.3$, and $11.2 - 13.3$, respectively. We find dynamical
evidence in all four galaxies for the presence of compact stellar components,
conceivably stellar bulges. The turbulence present in the galaxies appears to
be primarily driven by stellar feedback, negating the necessity for large-scale
gravitational instabilities. Finally, we investigate the position of our
galaxies in the context of local scaling relations, in particular the
stellar-to-halo mass and Tully-Fisher analogue relations.
