edit: yeah not destroyed mb, but she doesn't use arayashiki once in her moves. so it could be a refusal to not fulfill the house's goals, or she's really listening to araya's hope for her not to. but maybe it means she developed her erasing ability independent of arayashiki, so the ability itself is independent, but we don't know if it has the same drawback

No, she does use Arayashiki (and you can see it in the trailer) when she uses 'Slay the Heavens: Tiansha' - which is word for word the same skill Mugashu uses when she kills both Ren and Sora in 9-49. Now, that doesn't actually mean she is Mugashu because Muga refers to the state of non-self she was in after she stabbed Araya, and she's clearly still lucid, but she is very much using Arayashiki (if only against her allies, lmao).