Trying to take a strong form of OPs position, one obvious line would be the automation and mass reproduction aspects, in addition to how much unique creativity you specifically added to the process.

It gets of course harrier because what happens to experts in the field who are able to do that and then just use this as a boosting tool. Still, I don’t think copyright law has clear bright lines so much, but more guidance that the courts just try to muddle through as best they can. Certainly one can make an argument that just stealing an artists style like this could be considered a copyright violation, just like sampling even a few seconds of someone else’s track can be in music.

Again, not saying these are net good for society, but clearly existing copyright laws do try to take this tack. I think the one thing working against her favor is that a) early days so laws haven’t caught up b) us laws generally favor corporate interests over individuals so she might never get any relief even if deeper pockets start to protect themselves as this becomes a bigger problem for them.