Scientist suggests possible link between primordial black holes and dark matter
phys.org
phys.org
> A MACHO may be detected when it passes in front of or nearly in front of a star and the MACHO's gravity bends the light, causing the star to appear brighter in an example of gravitational lensing known as gravitational microlensing. Several groups have searched for MACHOs by searching for the microlensing amplification of light. These groups have ruled out dark matter being explained by MACHOs with mass in the range 1×10−8 solar masses (0.3 lunar masses) to 100 solar masses.
[1] https://en.wikipedia.org/wiki/Massive_compact_halo_object
Either way, the consensus cosmological model requires a non-baryonic component, which black holes don't provide.