I mean…did you read the light novels? I’m going to assume you did since you mentioned being a fan of them but sometimes people say they are fans of them but didn’t read them.
Look you can not like Saki if you don’t like her. Everyone isn’t always going to like every character in a show and that’s perfectly fine. People develop tastes and if she isn’t to your taste she isn’t to your taste. If you are familiar with Saki’s role and character in the novels and you still don’t care for her it’d be like me trying to argue with someone who read the novels as to why Seiji is actually an interesting character and not a bland piece of white bread. I’m not going to make you like her if you already know everything about her but still don’t like her.
Personally, this is why I like Saki.