I think you probably need some professional advice as this has been an ongoing issue. As a parent of child (now adult) with ASD who had issues with eating from birth, I didn't want to read and run.
The most important thing is not to turn food into a battle or make a fuss. The best advice I was given was to ignore conventional advice, go with what works for her. If she isn't underweight and her diet is okay, just leave her be. Let her stick to her favourite foods.
Things that helped DS were eating in front of the TV at his own pace (he got bored of eating at the table and would stop because he wanted to get on with something else, he also hates the sound of eating so the background noise helped). We only did that on week nights so we still enjoyed family meals around the table at weekends and did an after school snack and chat about the day at the kitchen table. As well as eating more, it also totally diffused the battle and stress around meal times, which was probably an even bigger help. It also made meal times fun and social again, even if some of those meals were watching a family favourite while eating.
Calorie intense foods were better for him so he only needed to eat a small amount (e.g. adding butter or oil to vegetables or cheese in potatoes, he also had prescribed supplements to add). Multiple small courses were often better than a big meal eg instead of serving pizza, garlic bread and salad, we would serve garlic bread as a starter, then a French style salad course, then pizza. Then 2 pudding courses, fruit (which he loves) and something calorie rich like a fromage frais, a Gu chocolate pot, cheese on a cracker, a small square of cake.
Another thing that helped was serving himself so he was controlling what he ate by choosing what he wants rather than controlling what he ate by refusing to eat what he was given IYSWIM? Seeing siblings and friends get excited about favourite foods and take larger portions than normal also helped. Although TBF the opposite worked at breakfast when he rarely had an appetite, plonking food in front of him meant he ate something rather than nothing. As much as I hate food waste, it is better than giving your DD long lasting food issues.
I'm not saying that any of those things are good advice for your DD but I am suggesting that conventional wisdom isn't always right either. The most important thing is to avoid making food into an issue and make meal times enjoyable.
FWIW DS is still a bit of a fussy eater but within the bounds of normal. I nearly cried when he took me to dinner at a Vietnamese restaurant that he was raving about after decades of the same meals over and over again. He also adds "hidden vegetables" to his own recipes because he knows he doesn't like them but he needs a varied diet.