ADHD child & focusing on tasks

I believe my 11 YO DD has ADHD. She is VERY easily distracted, fairly impulsive, and cannot seem to stop talking. She focuses reasonably well on schoolwork as long as she does it in her room where it’s relatively quiet and there’s not a lot to distract her. She has a terrible time focusing on household tasks, such as getting ready for the day and kitchen clean-up. She cannot even come out of her room to feed her guinea pig without getting wrapped up in whatever her brothers are doing and forgetting what she’s supposed to be doing. It is not practical in a household with 5 children to make sure she has a quiet space to do every single task that she needs to do–she has to learn to focus with some distractions.

I have tried timers, checklists, consequences, and rewards, and she still gets distracted constantly. When I try something new, typically it helps for a few days, and then she’s back to her old level of distraction. I’ve read the book Smart but Scattered. I got tired of having to stay on top of her and nag/remind her to stay on task, and stopped reminding her but added natural consequences, such as, if she’s not completely ready for the day by the time breakfast is ready, we sit down to eat and do RAs without her and she has to go finish getting ready. Thus far this has not made any difference in her focusing. But she manages to get ready quite quickly once she realizes she’s missing out on food/RAs, and if, say, a fun activity was starting soon she’d manage to get her chores done with minimal sidetracks. So I know she CAN concentrate, when she sets her mind to it…she just doesn’t choose to. I think she genuinely is very easily distracted, but at some point she needs to start trying harder to self-regulate, and that just isn’t happening. I don’t know that I buy into the line of thinking that says “she has ADHD so she just can’t focus”, because I see that she can when she wants to.

All that to say…I could really use any suggestions on how to motivate her to focus better. Or even on how to survive life with ADHD kids. I don’t like the idea of meds and DH would never agree anyway, but sometimes I wonder how much easier my life would be if she, and her 8 YO brother who’s pretty severely ADHD, were on them. I gave both of them DHA/EPA for a while but it made no difference at all that I could see. We’re pretty careful what we eat, no gluten, no dyes or flavors or preservatives, and it makes no difference.