Where Are All the Intermediate Mass Black Holes? Microlensing Fast Radio Bursts Might Reveal Them

In the heirarchy of black holes, intermediate mass black holes (IMBH) lie in between stellar mass black holes and supermassive black holes. But the problem is that we've never found one. There have been hints, but nothing conclusive. Could gravitational microlensing of Fast Radio Bursts help find them?