Hi there, thanks for playing the game and leaving a comment 😊
Salyra's whole purpose is to serve the Ancient Ones - but that doesn't make her infallible. She makes mistakes but it's also hard for her to own those mistakes and admit that she can be wrong. It's up to you to decide if the message/vision she received from the Ancient Ones was one that couldn't be changed or one that was caused by her meddling in the betrothal of Lamahu and Erlan.
Salyra married Ahlf because she thought her union with him would inspire peace between Ishari and Cyre - if you go down the divinity route and uncover the truth of Salyra's ritual when the MC was a baby, you'll learn that she thought having a child with both heritages who could wield their divinity would achieve peace. Don't lose sight of the fact Ishari was part of Cyre before the war - a lot of people on either side if the kingdoms like to ignore that fact, but Cyre and Ishari were one kingdom often ruled by Ishari royalty before Erlan started the war. Salyra didn't see an issue of being with Ahlf because she thought people would be reminded of this unified past and try to work together.
Salyra doesn't like Irus because he's the son of Erlan. She loves Anu, because Anu was trained under her regarding her divinity. She really hates Elora because Elora has proven to be capable and strong, openly defying Salyra which Salyra doesn't like.
In order to understand Salyra's character (I'm assuming you're going down the aggressive route with her), you'll need to understand she's a very flawed character. She is written to be narcissistic and controlling and if you're not going to appease her, you'll end up getting a lot of her more negative traits flaring up 😅
A lot of the confusion you have is valid - but that's the point. You have to come up with your own reasonings why Ahlf and Salyra acted the way they did and then decide if that's something your MC is okay with or not. You don't have to play a loving child - you won't be punished for hating the parents and it won't affect the outcome of the game other than your relationship with them. There are quite a few side stories on my Patreon that explore the past history of Salyra and Ahlf, but it's not part of the main plot which follows the MC's decisions and not Ahlf or Salyra's decisions.
I hope this helps clear up some your points 🌼