...so what female-focused Arthuriana did you find?

Because we were trying to come up with a counterweight to Bradley, we were looking for Arthuriana focused around female characters rather than just Arthuriana written by women, which unfortunately took out Mary Stewart, Phyllis Ann Karr, and Jane Yolen except in short stories. (She expanded a number of her Arthurian short stories into novels, but as far as we can tell it never happened with her major feminist retelling, "Evian Steel.") We counted Elizabeth E. Wein because of Morgause and later Goewin and rushthatspeaks remembered that Nancy Springer had written a Morgan le Fay novel; we weren't sure about Jo Walton because her relevant novels are so heavily reimagined from the traditional Matter of Britain, but then again we really didn't want to throw out Pamela F. Service or Naomi Mitchison for the same reason, Joan Aiken ditto, although we are now ranging very far from your standard retelling. The internet then informed us that we should also be looking at Vera Chapman, Sharan Newman, Persia Woolley, and Joan Wolf—one of whom we had previously heard of—and Catherine Rockwood specifically recommended Gwyneth Jones. So that's still a small body of work to start with, but it's much more than we were able to come up with on our own and strongly suggests there's more out there than half an hour of Googling can turn up. I just now remembered that Tanith Lee's "Into Gold" is female-focused stealth Arthurian, but it is again a novella rather than a novel. I would be very surprised if there weren't more short stories; they're just harder to find.