The fact that this is happening at both school and home. That it has been going on for several years and nothing has worked.....fits the qualifications for ADHD. And all of the symptoms that you have mentioned are also those for ADHD. I would talk with your teacher and school to see if you can get her tested as a starting point.
Wait, as a starting point - check out this link on ADHD and see if you think it fits.
I am also the CL on the ADHD forum here-
I have lots that I can share with you if that is what the problem is. For example, here are some ideas on discipline. https://www.additudemag.com/behavior-punishment-parenting-child-with-adhd/?utm_source=eletter&utm_medium=email&utm_campaign=april&mc_cid=575b694d3e&mc_eid=34d357d554
I hope this helps. If you have any questions, please post either here or on the adhd forum. Best wishes.