Did Job visit atrocities of the kind he experienced, on otherwise innocent righteous men in previous lives, and was this the karmic burden needing healing?

This is very much the case and, in addition to his transgressions causing pain to others and then to the loved ones of those individuals, he harmed himself and some of his own loved ones as well. Being close to home, the grievance is even larger, and added together, became a huge source of negativity that was overwhelming when it came in rapid succession from a series of such poor choices and the grief they caused. This is the dilemma of the perpetrator and that is the big lesson here, that victimization is not simply drawing the short straw, being the weak link in the chain, the most vulnerable, or the most unlucky individual to find oneself in harm’s way and take the punishment meted out by bullies, and so on. Oftentimes those who suffer greatest are the perpetrators of the past getting their comeuppance, having their handiwork returned to them energetically in like measure to the pain they meted out, directly or indirectly, as a consequence of their actions. The perpetrator ultimately suffers far greater harm and punishment than ever is the case for the victims themselves. Despite how severe or devastating the plight of a victim, the perpetrator’s fate will be far, far worse. This is guaranteed by the Law of Karma and will play out relentlessly and cannot be stopped other than through divine grace.