Sorry to hear the problem isn't resolved, that's gotta hurt. Just thinking of this, whenever problems arise in a mechanical assembly of any type, look back at the last problem area identified, don't know how many times over my career that has proved to be an invaluable clue. So in this instance, that would be the distributor, correct? What if the distributor bearing damage was not a cause but was damaged by some other issue? What connects to the distributor there- cam, oil pump, rear most cam bearing. Have you tried spinning up the oil pump by itself with a primer tool like this to see if that's where the noise is coming from? You may have done this already, I haven't read the whole thread.
https://butlerperformance.com/i-2445...-bpi-039p.html
BR's,
Mark