Someone once explained to me that autistic children live their lives in boxes. Home things belong in the home box and school things belong in the school box, so problems start when you try to put school things(ie homework) in the home box.
Another problem is that autistic children sometimes find it difficult to transfer skills, so they are able to do something in the school environment, because they have been taught how to do it there, but are completely unable to do the same thing in a different environment.
Our son had all these problems and eventually his school arranged for him to do his homework at lunchtime in the Homework club run by the support assistants. This was a reasonable adjustment and meant we didn't have all the aggro of trying to get him to do homework at home.
It sounds as though your daughter is struggling at school and is becoming stressed out by the demands being made of her. She doesn't need any more stress at home, so I would stop trying to make her do homework.
Instead, I would explain the problem to the school and if necessary, remind them that under the Equality Act, the school has a legal duty to make "reasonable adjustments" for students with a disability, so they need to either exempt her from homework, allow her to do it in school at lunchtime (with support) or come up with some other plan, but she will not be doing it at home.