Well, this story started off incredibly strong and fantastic. But as soon as the sister died the story just kind of had no real pay off. The sister died because of herself and the priest. There was a whole plot there but it went nowhere, just was cut off, the sister who honestly was the only real antogonist just never really became an antogonist. She was a brat, and listened to really bad advice but never felt that evil or bad, more just annoying. The priest who was the main antagonist the whole thing was insane that it went anywhere, so many things didn't add up. Like there were witnesses to how the sister poisoned herself and the FL, yet that never got brought up. Just hey the FL killed the sister no proof, then the royal family did nothing. The brothers and the dad are honestly who I hated the most there was no pay off there at all just oh. We miss our sisters and now they are gone, welp back to doing the exact same things we did before. One sister was a monster but she was never a monster in behavior. Honestly if Ashtarte had just left the palace at a younger age and went to another kingdom that would have made more sense. Then returned later to battle a horrifying homunculus who was actually powerful and taken over then that would have been awesome. Ashtarte's magic had almost no purpose in the whole story, the story could have almost been the same without it. She just would have needed to meet the Duke in a different way at a young age instead of random teleportation. She cured the diseases caused by the homunculus but that all seemed so vague and distant, not a personal threat. She did the huge magical healing thing that made her seem holy, but that was it, and seemed also very unnecessary like there were so many guards yet they couldn't stop an old out of shape priest with a knife? That was the big threat. Gods even showed up for no reason. The royal family could have easily solved all these problems if they were mildly competent.
Read Cursed Princess Club, it's finished and fantastic.