Been a while, but as I recall there are quite sensible rules on the noise the keyboard makes.
For various technical reasons "good" KBs tend to be noisy.
However as someone who moved to a keyboard at the earlierst possible moment, I have to tell you that some subjects like maths require a lot more time to input the stuff.
My issues were slightly different, no official SENs, but even then, it is extremely hard to type at what is effectively dicatation speed, especially if you are trying to think about the stuff, which is of course the idea...
Also there is a big trade off between quality of KB in terms of weight, and of course it needs to be attached to a computer. These are fragile and heavy.
There is technology to cope with this, but it's not all cheap
The first thing I'd buy is a cheap digitising tablet.
like these
Two sets of benefits.
1: A lot of class work is pictures, and DD needs to be able to capture this as well as the words.
2: It's a fun, cool toy. I'm betting that DD's morale with the writing gig is very low. Being told officially you're crap, no matter how nicely done, isn't great, been there, done that.
3: The software for this sort of thing is has "undo last screwup" feature. That means she can undo the errors.
4: Computers are patient, entirely non judgemental, and it's possible that if you also acquire a printer she can do stuff her mates can't. Big thing, and might help to reduce some negative reasctions from her peers.
I'd also look at web cams, make sure you get one that can take stills, and has enough poke to take pictures of the blackboard, which means not the cheapest.
I'd also look to see how DD copes with a microphone. Nowadays you can get MP3 gear that is tough, cheap (