Volumetric rates at z = 0 per black hole mass (top) and galaxy stellar mass (bottom) for different model variations (names of the models in legend as in text) compared with constraints from Yao et al. (2023, blue shaded area) and the fiducial model (red solid line). The orange shaded area was constructed by assuming no spin and maximally spinning MBHs in the post-processing treatment of the event horizon suppression of the fiducial model (orange solid line).