It's rather fascinating to find that in the case of M87*, the black hole and its accretion disk are counterrotating. A rotating black hole has a giant amount of

It's rather fascinating to find that in the case of M87*, the black hole and its accretion disk are counterrotating. A rotating black hole has a giant amount of angular momentum, and that has "accreted" onto it during its formation and lifetime; even if born from many mergers, and gone through billions of years of accretion, the current angular momentum / spin of M87* says that overall, what came together to form it all rotated largely in the same direction. The fact that M87*'s jet is straight also means the black hole can't have wobbled much in its (more recent) history. So why did the accretion flip ? How often does this happen ? How big is the influence of accretion (say, at high rates / eddington limit) on the black hole's angular momentum over time ? How long can such a counterrotating condition persist ? How common are cases where, say, the jet direction of a active black hole changed massively (or even reversed), indicating a "major flip" event for the black hole's spin ? (many questions just curious)