And then we have Cleopatra the last Ptolemy and she seems normal. Even the famous inbred Charles Habsburg have relatively normal sister. Nature really plays dice sometimes.
https://acoup.blog/2023/05/26/collections-on-the-reign-of-cl... gives a good overview of Cleopatra parents as we understand them. Note too different family trees - the official one which is so inbred as to believe it isn't possible her parents could survive; and the unofficial one that recognizes nobles often sleep around and so we have no clue.