  Observations with the James Webb Space Telescope (JWST) have revealed active
galactic nuclei (AGN) powered by supermassive black holes with estimated masses
of $10^7-10^8$ M$_\odot$ at redshifts $z\sim7-9$. Some reside in overmassive
systems with higher AGN to stellar mass ratios than locally. Understanding how
massive black holes could form so early in cosmic history and affect their
environment to establish the observed relations today are some of the major
open questions in astrophysics and cosmology. One model to create these massive
objects is through direct collapse black holes (DCBHs) that provide massive
seeds ($\sim10^5-10^6$ M$_\odot$), able to reach high masses in the limited
time available. We use the cosmological simulation code GIZMO to study the
formation and growth of DCBH seeds in the early Universe. To grow the DCBHs, we
implement a gas swallowing model that is set to match the Eddington accretion
rate as long as the nearby gaseous environment, affected by stellar and
accretion disk feedback, provides sufficient fuel. We find that to create
massive AGN in overmassive systems at high redshifts, massive seeds accreting
more efficiently than the fiducial Bondi-Hoyle model are needed. We assess
whether the conditions for such enhanced accretion rates are realistic by
considering limits on plausible transport mechanisms. We also examine various
DCBH growth histories and find that mass growth is more sustained in overdense
cosmological environments, where high gas densities are achieved locally. We
discuss the exciting prospect to directly probe the assembly history of the
first SMBHs with upcoming, ultra-deep JWST surveys.
