To mkirsch’s point. That new engine came out during the height of the Rona so as with all mfgs, less vehicles were produced and sold over the last 2-3 years.
Additionally, unless did hard GM and die hard gasser, the 6.6 was and still is the turd in the punch bowl. Anyone objectively looking for a HD gasser wood likely immediately dismiss the GM 6.6 for obvious reasons.
Lowest of the big 3’s other 3 HD gas options. The 6.4 Dodge, and 6.8/7.3 ford all make more power.
And to add insult to injury GM is still dropping the old 6 speed behind them when the other 2 mfgs have been offering 8 or 10 speed slushboxes for years now.
Not an excuse for an oil burning pig of a new truck though. Best of luck to the Op getting this resolved.