The supporting character's harem is very normal - Chapter 36 Sorry, Lathel...

Ye Qingli is the daughter of an Imperial Businessman’s first wife, wealthy and overbearing. But because of her mother’s early funeral, she suffered utter oppression and abuse under the hands of her stepmother. On the eve of her marriage, she died tragically in the hands of her stepsister and her own fiance!

Jiang Pengji got something called the Court Intrigue Stream System.
System: “Your goal is to become the most prestigious woman in the kingdom (the Queen)!”
Jiang Pengji: “Okay, System. No problem!”
Years later, she met the target by becoming the most prestigious woman (the Empress).
Jiang Pengji: “Well done, no?”

- Description from Novelupdates

She gave up her dream of shining on the ballerina stage —for him.She sacrificed her self-respect —for him.She forgot her true identity —for him.But even after all that, she couldn’t compare to the woman who held Ryan’s heart.Arwen Quinn, heiress of prestigious Quinn family, realized too late that no matter what she did, she would never win Ryan’s love. The future that awaited her was a life trapped in endless misery of a loveless marriage.So, decisively, she ends their relationship and walks away. What she didn’t expect was that in breaking free from Ryan, she had opened the door for Aiden to enter her life — a chance that he had been waiting for.Aiden Winslow, an enigmatic CEO isn’t just mysterious —he is determined, and won’t allow to take Arwen away from him again.____Excerpt:Aiden narrowed his eyes, “Are you sure about this?”“If I wasn’t sure, I wouldn’t have asked,” Arwen replied coolly. “Stop dawdling. If you’re unwilling, I’ll find someone else who can get the marriage certificates today.”His expression darkened as he pulled her close. “Once offered to me, it’s mine alone.”Unfazed, Arwen asked, “So, do you accept? If yes, we’ll get the certificates now.”“On one condition,” he said. “I don’t do contract marriages. The woman I marry will be the woman I share my bed with. If you agree, then we’ll—”“Not a problem. Let’s go,” Arwen said without letting him finish, pulling him into the Civil Marriage Bureau.

The chief female forensic investigator, Ran Yan was secretly killed by her assistant. Unexpectedly, she was reborn in the years of the Tang dynasty. After experiencing a narrow escape, she fled from Jiangnan to Chang’an. Although, Chang’an was at the beginning of its flourishing period under the Li family’s Tang dynasty, various princes were vying for the throne by using all kinds of strategies. This was the dark days of the imperial court, where one needed to walk on a tightrope as one’s life was as powerless as an ant. The Xiao family controlled a large amount of wealth so inevitably they also became involved in the conflicts.

After arriving in Chang’an, she discovered many suspicious incidents: the original owner had unexplainable amnesia but his family was indifferent. She once again saw the orchid shaped clay inkstone, a valuable object that her mother has given her in modern times. Hence, could it be that she can time travel back? In order to survive in the Tang dynasty, she displayed her strong spirit and willpower by learning medicine from a doctor, pretended that she benefited from being sick on how to cure diseases, suffered hardship in earning money, manufactured penicillin, cured syphilis, and used her autopsy skill and experience to solve each and every murder mysteries.

- Description from Novelupdates