Putting my hand up as another whose child was in a very different place by 4-5 grade. In fact mid yr 5 we moved her from a high end private school, where she'd had amazing support, to the local public, where she got absolutely no support at all. While academically she's no longer progressing at the speed she was at the private (making double the typical progress of her normal peers yr 3-5, in all areas), she is keeping up mostly ok. She still has issues, she's going to have life long issues, but its different to what lower primary was like.
Now I'm guessing that maybe somewhere you've talked about why you can't possibly homeschool, I find it hard to search on my phone sorry. But I'm unconvinced that you may not be the best teacher your child could have. My eldest is far from PG, but she is gifted, with extremely poor WM, dyslexia, CAPD & Aspergers. When she was 7, in yr 2, and still hadn't mastered the alphabet I didn't feel like I knew how to help, so homeschooling never really occurred to me, but looking back I was the most important reading teacher she had, that and TIME. I had no idea about phonics, I didn't know any of the decoding rules at all (no wonder I had such trouble learning to read and spell myself!), I had to learn how to teach reading, and I'm pretty sure I could teach almost any kid to read now if I had to. My interventions with math made far more difference than the special Ed she was receiving. Yes school put in a lot of effort and absolutely helped her, but I don't believe she would have made the progress she made without me and I do believe we could have gotten to the same place without the school. This is my child who took three (incredibly stressful) years to learn the most basic literacy skills: reliably recognizing the whole alphabet and being able to name by sound and name, plus reading readers to about end of K / mid yr 1 level took her until end of yr 2, mos of the progress in yr 2. By end of year 4 she was reading at yr 6-8 level (for non fiction), but still couldn't spell. By mid yr 6 her reading is years ahead, her spelling is supposedly age normal, her reading aloud still isn't great... I could not ever have imagined how far she's come 4 years ago, when I was battling daily for her to even look at the page of a book.
My second child has a hand writing disability, last year I was told to be happy if she grew up able to sign her name and tick boxes, and that she'd need full time keyboarding by yr3 at the latest. Last week she saw the OT again and she's now writing not just ahead of age, but ahead of grade (she's skipped) for speed, neatness, proportion. Her pen control is 2.2 SDs above age. She'll probably still need keyboard provisions as she may never have the strength for producing volumes at speed. But if it had been left to her teachers or even the best OT in our city, the conclusion was that her problems were either unimportant (teacher) or unfixable (children's OT and adult hand specialist OT). She can write now because I was determined to teach her and because she's HG+... Her hands haven't improved much at all and probably never will.
I'm not saying my kids' problems are the same as your DD, or on the same scale, but only that every day I am more convinced there is no-one more likely to understand or subsequently overcome their issues than me. We don't homeschool either of them right now, for various reasons, though we are getting ever closer to homeschooling our middle girl, but we absolutely are the ones most responsible for remediating their problem areas. Even at the awesome private school, with all the resources, neither of them could have made the progress they have without what I researched and implemented a home.
TIME and retular practice with a smart person who is always analyzing and thinking outside the box about what might help change the current pattern/problem is not to be underestimated.
