Is your dd against the structured, teacher-driven work? Perhaps she resists the practice and drill and kill approach? It sounds like your dd responded to your efforts to have her write something that motivated her and she was invested in. It also sounds like it's more a eg/pg, control, and motivation issues than anything else.
From what you're saying, your dd prefers to self-direct her learning. I would say try letting her getting bored for a bit and see if she re-directs herself to doing the math or talking to the teacher about making her feel more in control over assignments and work. I have to say that she sounds like my son.
We've been (and still am) in a similar situation with our ds who is in kindy and turned 6 years old this month. My son's in his second gifted school due to it; last year he whizzed through the pre-k/k/1st grade curriculum within 2 1/2 months and now refuses to do his 3rd grade math or much of any math. He's doing the minimum with writing though I think this second gifted school doesn't push the kindergarten kids on writing or much on the math either. My son isn't a kid who's passionate about any particular subject or topic either yet. Yes, we have the perfectionist and anxiety issues too. Sigh.
We've been holding off on homeschooling too, but am wondering what to do as well. At the moment, I cannot imagine homeschooling someone so stubborn and unwilling at times, though on the other hand I don't know how much he can continue to not make academic progress at a gifted school.
Have you applied for the Davidson Young Scholar program yet? I haven't yet, but another mother suggested to apply and eventually consider homeschooling.
I would perhaps speak to your dd teachers and school about acceleration and grade-skipping and see if that gets you any results.
