growth in the early Universe [e.g. @Shields2006; @Wang2013; @Willott2017]. However, observations of quasar host galaxies are challenging with current facilities [e.g. @Bahcall_1994; @disney_1995; @kukula_2001; @hutchings_2003]. These observations are strongly focused in two wavelength ranges where detectability is relatively easy: rest-frame ultraviolet (UV) emission observed in the near-infrared from $\approx{}0.7-2.2\mu{}$m, and rest-frame far-infrared (FIR) emission observed at sub-mm wavelengths. The UV emission traces the bright accretion disk and stellar light from the host galaxy, while the FIR instead predominantly traces cold dust in the host.

The extreme luminosity of quasars in the UV often means that they significantly outshine their hosts [e.g., @schmidt_1963; @mcleod_1994; @dunlop_2003; @hutchings_2003; @floyd_2013]. The highest redshift at which the UV emission from a quasar host has unambiguously been observed from ground-based telescopes is $z\simeq4$ [@mcleod_2009; @targett_2012]. Galaxies are more compact at higher redshifts, with physical sizes evolving as $R_e\propto (1+z)^{-m}$, where $m$ is typically measured to be between 1 and 1.5 [e.g. @Bouwens2004; @oesch_2010; @Ono2013; @Kawamata2015; @Shibuya2015; @Laporte2016; @Kawamata2018]. This rate of decrease of galaxy sizes toward higher redshifts is stronger than the increase in apparent diameters at $z$ $\gtrsim$ 2 due to the cosmic angular size–distance relation. Thus, at higher redshifts, the angular size of galaxies 