I have 2 reco but not exactly.
Mc is not part of harem but is an apothecary - Apothecary Diaries
Not a manga but a donghua where the emperor switched bodies with the empress - No Doubt in Us
I already read apothecary diaries but the second one's interesting, never seen a body swap between an emperor and empresss tysm for the recc! d(^-^)
Ehh, she isn't part of the harem nor is she a concubine/consort of any man (because the emperor is quite literally a child), but try this:
Koutei Heika no Osewagakari (the emperor's caretaker)
I absolutely love the (face of the) male lead there LOL
Does anybody know similar manga to this in terms of setting? I really like the imperial harem/concubine plot too but im having difficulty finding gud ones ╥﹏╥