Advice about teenage daughter

Hi all, Long post! And TDLR won't sum it up enough 🤣 sorry if there are any mistakes Not really sure where to post, I don't have many people to talk to but honestly just feel so lost! I have a 16 year old daughter, she was born 2008, I also have a 1 year old son who was born 2024. My daughter hates him, and I mean hates. She will not be in the same room as him, will not walk past him, not spoken a single word to him, if I speak about something funny he did she just tunes out of the conversation. Now before he was born we would have movie nights, every Friday and we still continued when he was born until she started not wanting to be around him. So he was born april, in November she was diagnosed with Autism and that's when it changed, she said she has a phobia and doesn't like children, but is absolutely fine with her siblings at her dad's. We went to see a therapist as she has been struggling due to GCSEs and she said to the therapist she wants us to do more things, but I'm stuck I can't just pop my son in another room and do things with my daughter but she won't do them if hes there. I mean she will climb over furniture if he so much as looks in her direction! She has a go at me if his routine changes and asks me to tell her, but again routine and change was never an issue before her diagnosis. I am fully aware these things are difficulties people with autism face, but how is it only after the diagnosis it's an issue? The therapist doesn't seem to want to help with that, and just says aw just do more movie nights...but HOW?! She will google everything and come to me with lists of diagnosis that she thinks she has, including schizophrenia and again the therapist just goes aww. She doesn't like any situation that isn't all about her, so his birthday she was in a bad mood all day, didn't utter a word to any of us. She has an excuse for everything and you cannot criticise or say anything as you'll get snapped at or the silent treatment. I feel awful and like such an awful person. I've tried talking to her but she's not willing to see anything other than how she feels, she doesn't care about anyone or anything else. She has even said if you speak and it doesn't interest me I've tuned out and that's literally every time I speak. The therapist is given her excuses to act the way she is even more, she has said if she has a bad day at school I should go get her, but now I know she will try to do this everyday. I feel like I'm stuck and it really is impacting my mental health too, which I'm masking. I just feel so lost :( I don't think she will ever like my son, no matter how much I try to do things with both of them, I still do things with my daughter on our own but obviously cannot be as regular as it used to be. Do I speak to a different therapist and just explain? Because I feel like this one has just ignored the pressure on the rest of the house. Also she is due to be 17 soon, and meant to go to college, but she won't travel on her own but will need to go on a bus so know this is going to erupt into something else come that time 😭😭 Please be kind, I already feel bad as it is!