  The extent of the effect of active galactic nuclei (AGN) on their host
galaxies at high-redshift is not apparent and studying this effect in the
distant universe is a difficult process as the mechanisms of tracing AGN
activity can often be inaccurately associated with intense star formation and
vice versa. Our aim is to better understand the processes governing the
interstellar medium (ISM) of the quasar BRI0952-0952 at z = 4.432, specifically
with regard to the individual heating processes at work and to place the quasar
in an evolutionary context. We analyzed ALMA archival bands 3, 4, and 6 data
and combined the results with high-resolution band-7 ALMA observations of the
quasar. We detect [C I] (2-1), [C II], CO(5-4), CO(7-6), CO(12-11), OH, H2O,
and we report a tentative detection of OH+. We update the lensing model from
Kade et al. (2023) and use the radiative transfer code MOLPOP-CEP to constrain
the properties of the CO, [CI], and [CII] emission and suggest different
possible scenarios for heating mechanisms within the quasar. Modeling from the
CO SLED suggests that there are extreme heating mechanisms operating within the
quasar in the form of star formation or AGN activity; however, with the current
data it remains unclear which of the two is the preferred mechanism. The
updated lensing model suggests a velocity gradient across the [C II] line,
suggestive of on-going kinematical processes within the quasar. We find that
the H2O emission in BRI0952 is likely correlated with star-forming regions of
the ISM. We use the molecular gas mass from [C I] to calculate a depletion time
for the quasar. We conclude that BRI 0952-0952 is a quasar with a significant
AGN contribution while also showing signs of extreme starburst activity,
indicating that the quasar could be in a transitional phase between a
starburst-dominated stage and an AGN-dominated stage.
