Get her a really unusual miniature from Etsy. You can find miniatures of virtually anything, and they are often quite well made. It will delight the lasting "child" part of her that likely still responds to tiny things, and you can customise what you get to suit her interests as specifically as you want to.
To give some examples of how a I have given these and it has worked well, I gave one to an older female relative which looked exactly like a much beloved family pet (the mini version is sitting on a tiny footstool), and just today as part of our couples advent as gave a miniature piece of kitchen storage to my spouse (the storage is for a particular food item that my spouse excels at making). They are basically dolls house size items but not really toys! More like tiny hobby items.
Bonus is they are very affordable and would be a charming small gift without using much of the budget.
If she has longer hair I would also consider getting an interesting / special claw clip. There are some really nice ones by Sui Ava that are prettier and more special than just a basic grooming item. Only if she has long enough hair to use it though!
Another idea is some washi tape from Etsy, because you can get really unusual and creative ones and it's very flexible in use. Can be used to stick up inspiration drawings, tear out images from magazines, etc, in her room (without damage like from sellotape), but also great in a journal, in cards, crafts and so on.