OP, I share your daughter's sensory issues, and there are loads of occasions on which I've bought something which I love the look of, tried it on at home, and found that it's uncomfortable in some way (fabric, scratchy labels - including some labels at the bottom of dresses - I'm like the Princess and the Pea with a scratchy label, fit, etc, etc. I have never owned any jeans because they feel wrong). So I can see why she wants you to buy things which she then doesn't wear.
However, I disagree with your desire for her to look "smart". She's just a child. My experience of having a girl with older brothers is that she wanted to wear the same as them and had no interest at all in frills and dresses. I admit that I enjoyed dressing her up like Princess Charlotte when she was a toddler, but she soon decided she was wearing her brothers' old t shirts and cords and shorts (all very soft and well worn and washed). Plus leggings. She went to a girls' school, and the girls were a mixture at your DD's age - some were very frilly, and others weren't. I don't think there's any particular pattern.
A PP suggested ballet flats - but I'd say that a child of 7 should be running around and playing, so they need shoes that are suitable for that, not something decorative.
Forget about her looking smart, and focus on her being strong and healthy. Above all, don't turn clothes into a battle ground.
BTW, I agree with you about crop tops on young children.