I was diagnosed with ADHD as an adult, and we suspect my six-year-old daughter may have it for a lot of the same reasons you listed.
We don't plan to have her diagnosed anytime soon, because we don't want to put that stigma on her. We wouldn't medicate her for it anyway.
It's entirely possible it's all just her being a six-year-old, so we approach her with patience and practical solutions. She lays out her school clothes the night before. We do our best to make meals interesting and varied. We have serious discussions about listening and give her gentle reminders. Her tv time is limited anyway, but we just pause it when we need to tell her something.
For my part, I don't know if my life would have turned out better with an earlier diagnosis. The way it went, I feel like I learned some valuable coping skills. And it's not like my diagnosis and treatment were some kind of magic fix. I still struggle with my ADHD.
A little more grace from my parents would have been nice, but they did their best and everything worked out with just a normal amount of grace.