Yeah, it's pretty uncommon, unrealistic, and un-immersive too to have 10+ harems... But fucking your 10+ colleagues and having affairs with your bosses, without necessarily they know each other, it's quite common in the real-life corporate worldCool. I wouldn't mind a little conflict & drama. Might give ya a good opportunity to flesh the characters out more? Maybe others are competing for promotions or there's a classic j-drama love triangle?
If you decide to add optional harem content; I hope you make it somewhat realistic. 2-3 girls with chemistry and/or legit motivations >>> 10+ girls that magically get along & put aside all their differences for cult leader protag.