
I just checked the official korean novel page for this manhwa, and it turns out that since the duke was so popular even among the korean fanbase, the author wrote a what-if side story where he’s the ML.
I think this gives us hope that maybe they’ll decide to make him the real ML in the manhwa version. But even if they don’t, at least we’ll still be getting SOMETHING.
Personally though, I’m still putting this on hold until it’s completed, just in case they DON'T give him a side story.

I feel so bad for the other Camilla. Being hated by even your mother for simply existing in a world you weren't meant to be in is so cruel. Was it ever revealed how she is doing right now? Did she die or is she alive in her og world?

I think that's one of the reason. Idk if the "hatred" towards the biological father plays a role on it too or not.
But yes.Their souls are not in the "right place", they are both in a wrong body, in a world they're not supposed to be. So the people around both of them unconsciously felt uncomfortable and disturbed by their existence alone. They will hate both Camilla and OG Camilla without even knowing why. That's why, now that they have switched back to the place they're supposed to belong, everyone is nice to Camilla again, because the uncomfortable feeling has gone away.

As someone who has read the novel I'll do my best to explain how this every-ml-getting-their-respective-ending thing works.
The alternate endings are like videogame ending, yk, those otome games?
1. With Swan it's the perfect ending. Shushu achieves her dream of becoming a magic knight.
2. With Corey, it's a sweet happy ending. But she ends up becoming a mage and opens a magic tower with Corey.
3. With the crown prince, it's an ending where they develop their sibling like bond even more. She doesn't end up with anyone romantically here, and she achieves her dream.
4. With the orange haired ml (I'm sorry i forgot his name), it's a bad ending. Like extreme possesiveness, mental manipulation and confinement, etc. of course the manipulation doesn't work on shushu, but she willingly gets confined by him. She doesn't achieve any of her dream here and basically gets isolated from the rest of the world.
5. With Hes, it's neither a romantic ending and nor is it an alternate ending. It's a continuation of swan's ending, so basically a side story about shushu's relationship with hes. Hes uses her remaining wish to dragon to send all the mls to an isolated island, so that they don't interrupt her time with shushu lol.
Why is everyone saying Swan's ending is the true ending?
It's because:
-every ml in their respective ending mentions how they are surprised that shuhsu chose them instead of Swan.
-since it's mentioned how shushu and swan are together in Hes' side story, it's pretty much confirmed.
-they also get a kiss in the main story.
But of course, everyone is free to choose their own preferable ending since the author themself gave us the ability to do so. So, don't let the facts (of swan being the true ml) get in the way of your ship!
It's so cute how his ears got red when he saw the fan made lunchbox!!!!!!!!
Can't wait for more interaction between Moondae and Cheongryeo (especially knowing what's coming, as a novel reader)