As for the TV series, it seems that she has a good relationship with Weiyang at present, and she also helps her when Weiyang has an accident. This must also be purposeful. She tried to use Li Weiyang to attack Li Changle. And now there is no deal with Weiyang, because Weiyang didn't stand in her way.
Li Changru helped Li Weiyang for three purposes: first, to suppress Changle; Second, help him win the trust of Weiyang (purposeful); Third, show off (for the king of Nan 'an). In fact, according to Chang Ru's personality, no matter which one, it is enough for her to stand up. You can see that she thought it over before coming forward. At this time, she should still want to be friends with Weiyang. She is willing to help Weiyang, but she is not willing to take such a big risk for Weiyang.