I would guess that Ruby has misinterpreted a mark scheme somewhere along the way. The guides put up for my subjects at uni (classics and English) both say that for an essay to get a first it might demonstrate an "original and imaginative approach to the question". If hers is similar, maybe she's gotten obsessed with the idea that to get a top grade she has to do something wildly inventive and original. The problem is, that's not really what tutors mean. They just mean when you're answering a question try to find your own niche or angle - an English tutor's advice this semester was "whatever the first texts are that come to mind for a question, don't write on them". It's not, come up with a completely original argument that no one in the potentially 100s of years since the texts were written has ever said before. Given her desperation to do well maybe she struggles to accept that. Also the same tutor told us that she didn't want us to write in exams on what she'd talked about in lectures/tutorials, so if that had been specified by Ruby's tutor I could maybe understand it? But my assumption is that that hasn't happened, and Ruby is just panicking over nothing.
Agree in terms of how annoyed her tutors must be. She must be an absolute nightmare to teach, and I bet her classmates all can't wait for modules with her to finish. It's wonderful that she's so engaged with the material, but she must be really taking away other student's opportunities to learn, and particularly given they won't all have come from such privileged backgrounds as her, that's really problematic. Also it's interesting that she always goes over word counts. I once asked why word counts were so limited (in my first year for English they were 1200 words), and the tutor said that anyone can write 1000s of words about something, but to be able to refine an argument so concisely was a far more important skill - it taught you how to use evidence/critical material selectively, rather than just using stuff with no discrimination. Our word counts slowly increased through the years, now in 4th year they range from 2000-4000 words (the module co-ordinator can choose). They expected us to learn how to make to the point arguments before increasing the word count. The fact that Ruby still struggles with that is kinda concerning given she's in her 3rd year of uni (2nd doing English, but presumably she wrote essays for her previous course).