@yotsuba428 - I ain't saying that her drugging Fuutarou, to throw off a tutoring session and then to escape his knowledge of her temporary abode, was the right thing to do; I disagree with the action more than anything. That's the only thing that makes me a detractor against her character. As now she's improved herself and there's been no mention of the events between Fuutarou and Nino, it's basically just a case of it's in the past and done, and she's a lot more respectable now her feelings are certain, making the protagonist start to face his inadvertent romancing of the sisters head-on instead.
At no point did I really make the case of it being about Nino protecting her sisters. Maybe at first, but that to me was more the case that she wanted no "outsider" in her home space, and definitely not the second time. Not sure on your language regarding her, either. I'm not above using the word myself but there's only a handful of characters in -all- manga that I'd outright name such, and Nino doesn't meet the criteria. Maruo, on the other hand...