I have severe dyslexia and dyscalculia. You have no idea how long it just took me to spell those words and in the end had to copy and paste the spelling from your post... that's how bad I am.
Try stimulating more than one sense at a time
For example instead of just reading or just doing maths try
PowerPoints
Flash cards - and dominos - make your own
Even let her use a fidget spinner while your going through questions
Try and get her to write out notes/ calculations that she doesn't know or understand and each one in a different colour and on different pages so she can try and visualise it in her minds eye so when asked that question again she may be able to think 'oh yeah I know this answer it was on the love of paper I had in pink pen and the answer was X' . This can also work with different music on in the background . I've heard people mention using different scents aswell. Like lavender in the room when learning a subject then lemon when learning another.
Bubble charts are good all different colours per question!
Does she likes sports? Could do a sports game like run to certain points in a park like in a map and has to find the answer before moving onto the next questions which obviously you can help her find the answer she doesn't have to suddenly know the answer because she's outside and not stressing at a table with a price of paper
Have nothing related to school work AT All in her bedroom so her bedroom acts as a safe space from learning which is hard for her at the moment. But when she's feeling for comfortable in the future have her write up notes and have them doted around the house, just never in her bedroom she will subconsciously take it in
Have a look at online games specific for what she has there's loads out there
Maths or spelling questions on the car
Also speak with her school when she's start in September about use of laptop in lessons and products such as claroRead ( have a look on google it will explain)
Has she had her eyes tested? Could get reading glasses with coloured lenses or a coloured overlay sheet
And above all tell her all is not lost. Once she finds out the best way for her to learn then things will really start to improve and even if it doesn't so what you don't need to be a mathematician or the best speller in the world to be great as she already is.
I survived, passed uni, albeit with several meltdowns and now have a brilliant job. Can I spell now? Absolutely not! Does a math question make me sweat absolutely yes! But perseverance is key.