but the other LIs have pretty much ONLY sentimental problems, tomorrow all of them except Bella (maybe, her situation is not clear), they might as well marry MC and drop out of college and live happily ever after.
Quinn has other problems to deal with, and starts way behind the others.
I never said she has to become an angel but some little hint I would already expect to see, some less abrupt passage in the dialogue with Tommy for example, instead it's always the old Quinn.
on the other LIs the effect of MC's presence is obligatory, he will be their friend anyway, for Quinn it's a precise choice, he should have a greater impact, which I don't see.
then if BADIk will last 20 chapters there's plenty of time, but the impression is that Quinn's function is marked