Wow!!
Despite the concern and frustration that you have had about your bike, the dealer support etc... I'm very pleased to hear that you've finally got to the bottom of it and now have the cause of the problem.....and.....it's an easy fix, which is fantastic.
I have to say, I didn't think about wheel balance. Better add that to the list of things to look out for.
Enjoy your 'new ride'.......and ride safe