So far, the important spells get their detail work done. How does the improved horcrux work?

AFAICT all Q's claims of its total novelty are in human speech. It's possible but not certain that his previous Parseltongued comments horcruxes puts a lower bound on how similar they are. It certainly means he's confident his ritual is not the one the legends are about, but given that it ended up suiting the stories better than the weak horcrux, it's quite possible he unknowingly reinvented the true forgotten original. (speculation: this would explain the possible-but-improbable appearance of a sixth-year able to outsmart and kill Baba Yaga)

We know it was expected to make him a disembodied possessor spirit but in fact required the victim to touch an anchor, until augmented with the resurrection stone. We know it requires a murder. We know the user is conscious while residing in the anchors. We also know that the legends it resembles say that it works by tearing the soul.