@wotm8
Yes you're the one not understanding something. A harem is a polygamous intimate relationship with multiple wives, not a group of girls surrounding one guy while none of them are dating.
No, you don't "see plenty of harem endings" in manga, outside of shitty isekai ones. Most "harem manga" have the MC either pick one girl at the end, or have no conculsive ending at all.
I'd fucking kill for a manga about a modern day contemporary setting where the MC gets an actual harem, and it actually develops their relationship after it becomes a harem and shows the sister-wives coming to terms with living together, sharing, and general romance between them and the MC. Then again, manga that show anything post-confession are already so rare that that's going to be nothing but a pipe-dream.