What do you mean? she could pass on her own? Riona never failed a class so far, at least that is what she tells camila. And no. I don't think she is manipulated. She is tolerant, that is different. Even if she gives Quinn a thousand of chances to fix her shit, doesn't mean she is being manipulated. She is very aware of what Quinn is doing. it is not like she is doing anything blindly, working as a puppet. Wasn't she the one who came up with the idea of using the freshman who was spending a lot on the girls?
You know who is manipulated by Quinn? Sage. The preps party is a good example. Lets not even talk about she not knowing what is happening with the girls of her sorority, her daughters, even all the conflict that happened between DIks or alphas, she just followed the way Quinn said it was. While Riona is well aware. She just accepts it, because she still sees Quinn as a friend and partner, and gives her chances to redeem herself.
I think we are playing 2 different games, because it is all about how you perceive things.