I'd argue that there's more variety on "White Chalk" than "Rid of Me"
Since "singular mood" seems to be one of your concerns. Sure, said variety is mostly in the instrumentation but I'd still say that "Rid of Me" is probably the most repetitive album of her career. And yeah, the performances on "White Chalk" are far more restrained than usual but it arguably suits the material. And that being said, there is still some "sudden vocal belting" as you call it on a few songs.
I also think the songwriting on "White Chalk" is generally stronger but IMO Harvey's pretty consistent in terms of quality- "Stories From The City" and "Uh Huh Her" are the only albums of hers that I'd say are noticeably weaker than the rest.