As to the "nuanced interactions" things, it's interesting to compare the new chapter with the aquarium date. There Yuu and Touko are being cute and happy together, but the nuance comes from the disconnect between what Yuu feels and what she feels able to express because of The Toxic Contract.
Touko tells Yuu "I love you," and Yuu knows that she's not allowed to say it back. Yuu grabs Touko's hand to lead her through the crowd, and they keep holding hands (to Touko's delight), but later she doesn't feel free to take her hand when Touko is sleeping on the train (a callback to Yuu resisting the impulse to hold hands when they were taking shelter from the rain).
As BugDevil says, the primary tension and ambiguity of their relationship has been resolved, so the same actions and behaviors that once were so fraught with meaning and possibility now are just . . . fun.
As Yuu's question about being "girlfriends" implies, there are still plenty of potential "nuances" to work through going forward.