Anyone local to me capable of correcting errors on a 904 race build

I agree with what you have said, however
a business person who was short with me on the phone, won’t deter me from persuing
$$4,500. And there is no way I would then spend another several thousand dollars somewhere else to get the problem resolved.
That is on the Op.
Read your post I quoted

And there is no way I would spend another several thousand dollars.