It's only really harem in the sense that the MC is male and the majority of the rest of the cast is hot females. And even better: the hot females are not all madly in love with him! The MC is only interested in one of the ladies and they do eventually get into a monogamous relationship with no dumb communication issues getting in the way. There is one other lady that loves him and it might go somewhere eventually but as of chapter 600 it's still very much one sided.
As for fan service...I wouldn't say it's horrible but also not non-existent. For example, all the characters have only one outfit they always wear and a lot of the womans outfits do tend to be on the revealing side. But each character is put to use so it's not like they only exist as fan service. Overall, I'd say it's easily tolerated if you find the story interesting.
Donghua has started airing.The characters' personalities, appearances, and clothing designs are really well-designed.From what I understand from the first two episodes, I don't think there will be any silly fan service, and it seems to me that it will be a monogamous marriage.He marries Anna, and hopefully the other female character isn't reduced to just a woman who falls in love with him. I haven't read the manhua version of this, but Donghua gave me a certain vibe.

How is this? It's marked harem, which I don't mind too much, but what about the fan service? That I don't like at all.