Indigo I hear you. I hear everything your saying.
BUT as awful as this is, your child's ONLY hope for sorting this is you.
You're frustrated because what you have tried hasn't worked. You are frustrated because you don't know why. You are being told that it is something about your dd by the 'professionals' (or info on her condition) that is causing the issue. You are being told here that it is something about 'you' that is causing the issue (i.e. your inability to perfect the teaching method that works).
You don't believe in yourself and your ability to make a difference. If you're anything like me you'll be bloody angry that you should have to and quite depressed at the amount of work it might take and the sacrifices you have to make and the forced on your other children(?).
I'm not very good at saying what I am about to say, although I know I can be blunt sometimes but I think you need a bit of a kick up the bottom.
Take those CVCs and work on them every day, maybe twice a day if you can get your dd to do it. Do it at the same time each day as part of a routine. Put the ones she gets in a pile and the ones she doesn't in another pile. When she gets an additional one to the session before, celebrate like mad. If she gets one less just ignore it. You can keep a lovely block graph so she can see herself her progress.
Analyise within an inch of your life, the ones that she is having difficulty with. Do they all have b's and d's in them, or a particular vowel. If so, you can start a different CVC programme concentrating on the area of difficulty.
In terms of working memory issues there have been some things suggested here. My ds loves the physical games with instructions so 'ds clap your hands and spin around - yay brilliant now lets play with the fan'
If he doesn't do it, then you repeat the instruction whilst physically getting him to do it.
Once he gets 100% for that a few times it is 'ds, jump, touch your nose and hop'
It has taken a year since we first started this but now ds can follow instructions such as: 'ds, go into the front room, get the red ball from the sofa, go upstairs and put it on dd's bed' (we would have a variety of balls in the front room etc.)
I'm very VERY lucky however. DS progresses at a rate that whilst slow is still fast enough for it to be rewarding for me to teach at my own internal patience levels. I am rewarded for MY efforts in teaching him. I can image it would be harder to keep up the practice if the time period had been 10 years and not 1.
Could it be that you aren't giving any strategies long enough or being precise enough to be able to see the progress? Or perhaps breaking things down small enough.
With the CVCs could you start with all the ones ending with 'at' and just canging the first, being a bit more systematic?
ALthough I have to admit that I have yet know knowledge about how to teach reading, just an understanding of how you break things down, and then some more, and then some more. Generally the smaller you break things down, the more likely you are to see the progress.
Anyway. Hopefully just some ideas for you to think about. You will figure it out because you are a good parent and quite frankly who will if you don't?