I can see why the KB Co. went out of business, I would get a different keyboard since you've exhausted the other options, it appears, although I wonder if a 3rd party mouse tool could have fixed that.
overriding mouse driver
features and vice versus, that's a new one.
How old is that keyboard?
I go through keyboards 12-24 months at the most, typically before I need a new one.
[That's my excuse for replacing, any how, YMMV]