  We measure host galaxy stellar masses for a sample of five luminous quasars
at $z\sim5-7$. Using JWST/NIRCam medium-band images of nearby PSF reference
stars, we carefully subtract the contribution from the quasar light to place
upper and lower limits on the flux of each host galaxy. We find that the
members of our sample of quasar host galaxies have masses of $10^{9.7} -
10^{10.8} M_{\odot}$, significantly less than expected from their SMBH masses
and the local \magorrian relation. We additionally obtain JWST/NIRSpec IFU
spectra of three of our quasars to calculate black hole masses, which we find
are consistent with those in the literature, and to search for the presence of
a bright but compact galaxy via a Balmer break, which we do not find evidence
for. We discuss the potential effects of dust extinction on our measured fluxes
and the impact of selection effects on high-redshift quasar samples. We
conclude that the masses of the SMBHs relative to the host galaxy stellar
masses have a much larger scatter than locally, large enough that these
selection effects cannot be responsible. The result is reinforced by other
studies. Finally, we explore the potential implications of these results on the
picture of SMBH-galaxy coeval growth in the early Universe.
