There is a reason exams have a set duration, a reason why the questions are designed according to the ability to suitably answer them within a given time, and a reason why so many children end up doing poorly/poorer than if those who had longer to think about the answers/draw clearer diagrams/plan their answers, because they ran out of time.
You don't seem to understand specific learning difficulties. I raised concerns with the school about DD2 from age 12. I had her assessed privately by a speech and language therapist, and a leading neuro-educational psychologist at 16. The psychologist detailed in her report how DD2 cannot extract much meaning from language. She has to read a sentence or replay what she heard in her mind three times to work out what it means while more language is pouring in. She can't follow instructions or recipes or films or books or conversations, unless its short answers to her questions. She has difficulties with planning and organisation, including her thoughts - she spends an hour a day, looking for her phone and keys. She forgets all appointments, unless they text her reminders. She finds it difficult to put thoughts together - for instance, she can't write a story. She cannot visualise from language - such as describe what a scene in a book looks like.
The psychologist recommended 25% extra time in exams to give her more time to read the questions; plan her work and read it over (as she makes silly mistakes).
She was in a such a state about her A-levels (being suicidal), we only got her to take them at all, by taking her to the GP, who prescribed her Prozac.
The local state school refused to give her extra time in her A-levels, saying there should be a level playing field.
I had to threaten to take them to court for disability discrimination; and then they allowed her extra time in the rest of her A levels.
After being suicidal 6 times in her first year at university, she was diagnosed by a the mental health team with ADD. Imo, the stupidity of her school, while not the main factor, contributed to her mental health problems connected to studying. What is the point of a teacher telling her in the 6th form she was scatty - when that is exactly what ADD is like, and it has disastrous effects on self esteem?