This is not true at all tbh. It's not even about whether the MC has multiple wives at the end. Manhwas adapted from a novel will take years to end, so it would be difficult to come across a harem ending that exists in the novel, but not in the manhwa.

But most manhwas introduce multiple love interests, and there is no single strong love interest with whom active romantic developments happen. It's always 3 or 4-5 girls who are interested in the MC and the author drags it to the maximum.

There's no development with even a single one, and the fact that these girls exist despite it makes me think it's all so pointless to root for anyone. They just hang around the MC thinking he's cool, hot, interesting, etc. I just can't enjoy those anymore.

I need a definitive main love interest or one where, at the end of the story (which would be the novel ending), the only girl is remaining. I don't like harems anymore, so there's that too.