What you describe with your daughter sounds exactly like the inattentive form of ADD/ADHD. It’s often accompanied by low energy levels and fatigue, especially for people who aren’t on meds. I think that is largely because trying to stay on top of everything, when you have what is primarily an executive function disorder, is very tiring!
I don’t understand your reluctance to at least do a trial of medication for your daughter. It could make an enormous difference to her life and her happiness. I was only diagnosed at age 30, and my life would have followed quite a different path if I had been diagnosed as a child, and received the appropriate medication to assist me in managing my condition. I don’t blame my parents because they didn’t know what was wrong. But, if I had received a diagnosis and they had deliberately withheld the medication from me, I would have found it very hard to forgive them! Despite being a member of Mensa, one legacy I’ve been left with, is a sense of failure that overshadows everything I do.