In my experience the right school will make all the difference in the world. Have you chosen her school and if so, does the headteacher understand adoption and the challenges that come for adopted children? That would be my first stop tbh, my daughter has a lot of developmental delays which her school accommodates and supports really well.
Work on what she can do, colours and numbers, help her begin to identify letters, eg does she have an easy name that you could help her with. In terms of learning research shows that the one thing that makes a difference is parents reading to and with their children, which is something you can easily do.
In terms of her fine motor skills, I was told to work on the major muscle groups first, so lots of climbing, hanging from bars, lots of big circle shapes (eg writing in the air making shapes so her shoulder muscles are well developed to support fine motor). I’d she mark making at nursery? There’s a school of thought that says learning pre-7 should be wholly play based so maybe look at play based learning.
My DS started school at 5, usual age in Scotland and couldn’t write or read - his development now is exactly where it should be because the school know how to support his learning. Are you in England? I often think there’s far too much expected of reception and year 1 children down south never mind for kids who have had a hard start.
Worth asking the nursery too whether they see early learning blocks in place or whether there are things you could do to support.