Yua and Serena have always been like this, even before the MC came to the Human Realm. That's why Dyna said, "Can you two just be nice to each other for once?" when she tried to stop their argument. With the MC (Noah) now here, Yua's dislike for Serena has deepened due to how strict Serena is with him. As for Liana and the MC, Yua jokes about Liana being nice to him because, for Yua, that's out of character for Liana. Plus, Yua is Liana's best friend, so these types of jokes are usually not taken seriously. So currently, the way Yua acts toward Serena is purely because of her relationship with Serena, not because of the MC... YET!