Had a dealer reach out to me another forum, I am going to send back my faulty unit to Sony for the buyback.
The forum dealer is going to price match my original unit ($2700), so I can essentially swap out units for a new production one. My original unit was bought March 20 (so probably a round 1 batch), I will compare serial numbers and see if the new unit still exhibits the same symptoms. The dealer does have a 90 day return policy as well which should allow adequate time to work through any glitches should the arise.
I still think this was a first run production issue based on Sony's hesitancy to admit fault and mysterious offer to buyback the unit but not even attempt to exchange it, I have also noticed on this forum and a couple others, more "hiss free" units being reported (and an increase in 'ding/dent' sales) - which seems to imply a lot of first runs being returned, while newer units are coming out better.
If it still exists there the plan will probably be going to a Denon A1H as I need a 13 channel Amp AVR and then do Dirac for room, speaker treatment - and that timeframe might work out with Dirac's DL ART room correction.
Fingers crossed that I get a unit from a newer run and the issue is mitigated