Your mistake is in thinking it reaches from the lower clergy up to the chanceries.
Rather, it extends down from the curia (and now, perhaps even the papacy) on down to the national bishops’ conferences, to the chanceries, to the pastors, to the individual priests, and then the seminary directors who recruit fresh meat into their homoclergy demonocracy.
I don't think that the abuse flows from the lower clergy to the higher. I think that the secular investigation --- the grand juries and so forth --- are likely to start with the lower, and work up to the higher.
Most of the abuse is old news: even the PA AG report was mostly stuff that was already reported in the John Jay report. (Want to know how many cases they found from the last 10 years? Hundreds? Dozens? No: two. That's right, two. And they had already been reported to the authorities by their own dioceses.) What's NEW is the focus on not the abuse itself, but the complicity of the higher-ups in cover-ups and pay-offs.
And possibly, also, there will be a new focus on the exploitation of legally of-age victims --- seminarians and young clerics --- over the age of 18, which makes up the bulk of the disgusting, sacrilegious pile of vice known as the McCarrick case.