Thought I would post an update.
Decided to try the cheap, easy fix that I watched on a couple YT videos.
I built a diverter (upside down V) from some pieces of solid insulation, completely covered with silver foil tape. After sealing all possible air leaks in both bays (intake and cold air supply) with the same tape, I secured the diverter in the cold air bay. This effectively blocked the cold air straight dump, and diverted cold air to the two ceiling ducts. During measurements and design, I ensured optimum (from a layman's perspective) air flow to these ducts.
Once done, although we lost the straight dump, discovered the noise had dropped considerably and the cold air coming from the remote vents was noticeably greater. In fact, funny thing, by doing this I discovered we had a 4th a/c vent in the bathroom which, up until now, was so low/no volume, we had not even realized it was there. Go figure.
Total cost $10. Total time, less than a day.