Man, this story is a hot mess. Post-apocalyptic power abuse where everyone is a horrible person... but they are all hot, somehow, so it's fine, I guess?
Side note, they'll probably clear this up later, but I'm confused. So, Wu Qing, the maid, is a robot made in the likeness of Xiangsi's former lover, who was also named Wu Qing? But why did they show Wu Qing getting sold to the black market?
My guess is that the original Wu Qing was sold on the black market to Xiangsi, who treated her like dirt at first before falling for her. Then, however, she did something that resulted in Wu Qing's family dying, prompting Wu Qing to turn against her, after which she also perished (killed by security?). Later, Xiangsi has a robot commissioned to look just like Wu Qing and gives it (her?) her lover's old name because she cannot let go and wants a second chance.
I gathered that the original Wu Qing was just a regular friend of Xiangsi and the "mistress" thing was just them goofing off; Xiangsi reminisces about their friendship and fallout after the robot version introduces herself.
The robot version seems to be a Trojan horse manufactured by the ladies with the red hair and pink hair to get close access to Xiangsi. The sale of the robot through the black market, along with the memories she seems to carry, are a charade meant to obscure her true origins from both herself and Xiangsi. The fact that her creators still named her Wu Qing may make for pretty bad opsec, but maybe the name is meant to hurt and insult Xiangsi just like the face.
My takeaway from "it was you who killed my parents" is that the original Wu Qing's parents died due to the incident involving the plague vaccine that Xiangsi worked on. It would not make sense for public opinion turn against Xiangsi for causing the death of Wu Qing and her parents if they had been of low status, which again makes it unlikely that the original Wu Qing was sold to the Yao family.
Your version appears to be closer to the canon than mine, I stand corrected. :-) What confused me was that the robot maid thought about her family and sister, but it must have been just memories implanted by pink+red hairs for verisimilitude. Also, when Xiangsi talks about "testing [her] so many times", she appears to be talking to Pink through the robot maid, so it might not even be Pink's first attempt.
Also, I have noticed on re-reading that the original Wu Qing had worn a choker/collar, so her calling Xiangsi "mistress" may have more meaning than just friend goofing around.
