A semi-analytical model for the evolution of galaxies and supermassive black holes (SMBHs) within the ΛCDM paradigm has been shown to yield stellar mass-BH mass relations that reproduce both the JWST and pre-JWST observations. Either fuzzy or warm dark matter (FDM or WDM) would suppress the formation of the smaller galactic halos that play important roles in the CDM fit to the high-redshift SMBH data. Our analysis of the stellar mass-BH mass relation disfavours FDM fields with masses < 2. 0 10^-20 eV and WDM particles with masses < 7. 2 keV, both at the 95 % confidence level.
Ellis et al. (Mon,) studied this question.