Can someone give me few suggestions of brilliantly written harem, polygamy stories with or without action or adventure as main genre?
I think it's brilliant, in a manner of speaking, harem/polygamy story. But I don't think this is what you were asking for https://www.novelupdates.com/series/despite-being-pursued-as-a-villain-all-the-heroines-on-my-side/
The Deer and the Cauldron This is an easy recommendation because it's literally the best book on NU and it is the progenitor of all the Chinese harem novels. You can feel all the different things that other writers took from this book, and how even after all these years, the original has never been topped. To be fair, while the harem itself is one of the main things readers will take away from this story, there are other elements that are a bigger deal. That said, the interaction between the protagonist and the female characters is still really fun to read (mostly because he's such an ass!). Other than this, the other books I'd recommend are all in Chinese: 回到明朝当王爷 步步生莲 醉枕江山 However, I don't think that you should be reading these books unless you know Chinese. They have large portions written in Classical Chinese and have a ton of era-specific terms so MTL for them would be much worse than usual.