Responses
I would also add that, to have the emperor eventually falling in love with her, and abolishing the harem system, though unrealistic but possible, is something I am looking forward to seeing. (There was another work that abolished the harem system, but it was done so horribly, I was not satisfied and left so many questions and it just glossed over the reprecussions just like that.)

I don't get the seething rage against the emperor. It's customary practice for an Emperor to have a harem of beauties (to not have one was seen as not normal, actually) and has been a long standing customary obligation that the Emperor needed to fulfill, to produce a male heir to the throne. For such reasons, the harem exists. Automatically fangirling over the second male lead on that basis, while we know nothing at all about second male lead at all, is something I don't understand at all.
However, the queen's power ranks above the consorts, as you could see here. Hence, you get all these palace politics and schemes that the women battle through (some end up in tragic fates, see real life example of concubine 'human swine')