  Magnetic fields are widely recognised as critical at many scales to galactic
dynamics and structure, including multiphase pressure balance, dust processing,
and star formation. Using imposed magnetic fields cannot reliably model the
interstellar medium's (ISM) dynamical structure nor phase interactions. Dynamos
must be modelled. ISM models exist of turbulent magnetic fields using
small-scale dynamo (SSD). Others model the large-scale dynamo (LSD) organising
magnetic fields at scale of the disc or spiral arms. Separately, neither can
fully describe the galactic magnetic field dynamics nor topology. We model the
LSD and SSD together at sufficient resolution to use the low explicit
Lagrangian resistivity required. The galactic SSD saturates within 20 Myr. We
show that the SSD is quite insensitive to the presence of an LSD and is even
stronger in the presence of a large-scale shear flow. The LSD grows more slowly
in the presence of SSD, saturating after 5 Gyr vs. 1--2 Gyr in studies where
the SSD is weak or absent. The LSD primarily grows in warm gas in the galactic
midplane. Saturation of the LSD occurs due to ${\alpha}$-quenching near the
midplane as the growing mean field produces a magnetic ${\alpha}$ that opposes
the kinetic ${\alpha}$. The magnetic energy in our models of the LSD shows
slightly sublinear response to increasing resolution, indicating that we are
converging towards the physical solution at 1 pc resolution. Clustering
supernovae in OB associations increases the growth rates for both the SSD and
the LSD, compared to a horizontally uniform supernova distribution.
