If you haven't already read things about fixed vs growth mindset, e.g. Mindset or (more academic) Self-theories by Carol Dweck, I would really strongly recommend doing so. In order to know that it's sensible to try, you have to understand that doing so will make a difference - and if there's a gulf between areas where learning happens so fast that you hardly notice, and other areas where it happens so slowly it looks as though nothing is happening, this is not at all intuitive. It needs to be taught and demonstrated to be true.
My DS hit this with piano, which was the first thing he'd really had to struggle with. What helped: practising every day, with one-one support, for a decent chunk of time; focusing more on the practice habit than the improvement, i.e. audible improvement was great, but I tried not to let him expect it every day or feel he'd failed if it didn't happen. In fact, what happened often was that he'd have a particularly frustrating day in which it felt as though nothing was getting any better, and then in the next day's practice that thing would "magically" get better; we learned to say "your subconscious was working on that!" and then "your subconscious needs to get working on that, give it the practice it can work on" since that seemed to be a decent model of what was happening.
It was a struggle! (And DS shared several characteristics with your DD at that age - in fact his teacher used the "walking on eggshells" phrase to us to describe it.) But it did get easier.
The thing I think was really helpful about piano as arena for this learning, which might not be automatic in the areas your DD needs to work on, was that he really was working at the very same set of movements every day for a week or two. That made it very obvious when he was improving. With writing/drawing, it might be harder to see an improvement; perhaps you might need to manufacture a stable task she could do every day for a while, and that could be varied and made harder over time, specifically so that she could see improvement?
I'd also say: if she likes to draw things that look like scribbles and tell stories about them, make sure she gets opportunities to do that, too.
