I find Walton's King's Peace and King's Name amongst the very few coherently thought-out Arthurian retellings of the last few decades. She does very good worldbuilding. (Prize in the Game is set in a compatible ancient Ireland but isn't strictly related.) I must say, though the rape in KP bothered me as a story gimmick, it also felt entirely plausible in-story. That protagonist is supposed to be the one-in-a-million person for whom certain stereotypes are true, for well or ill. I wouldn't say I'm entirely a fan of Walton's work, but I respect her research and the way that she combines it with the story she wants to tell in KP/KN.

And yes, Tooth and Claw is great, and a very different sort of book in some ways (yet not in others, which is a good thing).

Another well-built Arthurian, YA-compatible, which goes sideways (in a good way): Elizabeth E. Wein's trilogy, beginning with The Winter Prince.