I am so sorry to hear of your daughter's challenges. I went through very similar surgery and treatment about three years ago.
Radiation destroys your taste buds and it takes years for them to recover. A couple weeks after radiation, my flavors were still completely jacked up and I was down to about 15 things that I could stomach. Some examples - green beans, scrambled eggs, pancakes, french toast, vanilla pudding/ice cream, avocado, noodle soup, think super simple! Plus, try blending things. A couple months after radiation, I could slowly start adding fruit (the ones with less citrus like a banana blended into protien drink, with vanilla ice cream and an avocado) and other simple foods (careful of anything spicy!). Ketchup was hard, pepper, salad dressings, etc. After three years, I can eat most anything but still have to avoid spicy stuff and alcohol (tastes like poison). And, I still see some improvements such as I can eat a little ketchup on a french fry straight up now. I have heard this flattens out after about 3 years. So, I can offer you hope. I now eat out at any restaurant and I am just cautious about the spicier stuff.
I have also had lots of dental work (crowns and root canals) done. I had lots of fillings before my treatment so this is most likely just a result of rads accelerating the damage.
Happy to help answer any other questions and thanks for reaching out. This forum has a been a huge help to me as i recovered and I hope it can be the same for you and your daughter.
Stay safe and keep the faith,