Anime with a 'real' harem.

Usually when it comes to harem anime it usually is just an upgraded version of a love triangle where more than two characters are vying for the affection of the, usually male, lead.

Are there anime that depicts a functional polyamorous and/or polygamous relationship as a classical understanding of a harem would lead towards?

I believe this most often is depicted in hentai and adjacent properties but I'm not interested in the sexual nature of the relationship but instead the interpersonal relationship being in a harem would actually tackle.

So yeah any anime that depicts a protagonist in a polygamous relationship, no ambiguity about it, all the harem members are aware that they are in a harem (otherwise it'll just be cheating), and isn't just hentai?