
What i think happened in terms of her reincarnation is that she lived her life in this magic world without knowing about her past life right until the queens candidate ceremony where she is suddenly hit with memories of her being a shitty person in Japan.
But because this manga has lazy writing, it just makes it seem like she died and was plopped inside another person's body with no explanation about why she thinks that she worked her entire life to become queen.
Its kinda hard to tell with Japanese reincarnation stories because some get put in fully grown bodies, while others start off as children.

This is becoming Mary Sue levels reaaaaaally quick lmao. Like, ok, your fat melts off due to magic, fine. But now she makes these high purity magic stones out of thin air without any real trouble and I hear that she just manages to summon the HIGHEST level spirt ever when she has never tried it before? I get that this life is supposed to contrast how shitty her past life was, but that's not even the real daughter, its a reincarnator.

I started to get the feeling she was a Mary Sue when she found Tev.
Like she is supposed to know the future but while coincidentally sneaking out she save someone after coincidentally running into her sister and helping her too and that person she save coincidentally turns out to be someone super important who coincidentally get attached to the first person who help him.
It was a bit too much. She didn't do anything but everything went 200% her way.

I actually think the prince did love the original Alya, but because of his twisted personality he got tired of Alya's monogamous/possessiveness, which is why he decided to shack up with a white lotus bitch (which he is aware of her true personality) so that he could be in control. Its possible that the two were once lovers, which is alya curses him to love only her. This is all speculation and I haven't read spoilers yet, so please tell me if I'm wrong ヾ(❀╹◡╹)ノ~
Imagine if people went to a Yuri comic and said make it straight lmao. I get it, y'all ship it, but there's no Yuri tag so don't be disappointed when its not yuri.