As I noted in the OP, I have a backup system that I use and like. All my documents I store on my local drive and I don't use OneDrive to store my documents unless I specifically want to.
But OneDrive keeps prompting me to backup my documents on OneDrive, even those ones that I've specifically saved to my local drive.
This looks an awful lot to me like Microsoft is just pushing for users to use OneDrive - but I don't want to use OneDrive (except for those few documents I do need OneDrive for).
So without uninstalling OneDrive all together, how do I get Office/Windows/OneDrive to stop prompting me to backup my documents.