Op, if you're looking for a quick fix or some kind of technique to cure your daughter's fussy eating and she'll start suddenly becoming interested in food I assure you there isn't one.
You need to learn to let go, you can't control what or how much she eats. Life becomes a lot easier if you just accept she's small, fussy and eats like a sparrow. It's not bad parenting. It's not your fault.
Hugs again. No judgement here. I wish you could just relax a bit more. I have my moments too of utter dispair (like when we visit the inlaws for meal times, they are full of judgement, mealtimes are painful) but she is who she is, and eats what she needs.