Update for anybody that gives a damn.
GM rep called 2 days ago and indicated they sent the dealer options for me. I called the dealer and they indicated they'd received nothing from GM. GM rep indicated she would call me back yesterday, no call back.
Service manager called yesterday morning and indicated GM is basically putting my case back on the dealer to provide me a good deal on a trade. Problem is, they're just now starting to take orders on '25's, and I'm not trading a '24 on a '24, so it will be 3 months, give or take, before the '25 would come in and the dealer understandably won't commit to a trade in value on the truck at this point. And, it's not on the dealer to make this right (although I told them if they want to keep my business they're going to have to give me one helluva deal on the next one), it's on the manufacturer to make this right . . . in my mind, anyhow.
Yesterday, I spoke to a lemon law attorney and was told I have an excellent case. He said that based on my truck being in the shop for repairs for almost two months, I have an excellent case and that if I pursue, I would likely end up with 1) a full refund of purchase price; or 2) an even trade for one of equal value when mine was new; or 3) a cash settlement equal to the difference between the MSRP and current trade in value. I haven't signed with them yet, was waiting to hear was GM rep has to say if/when she calls me back, but since she didn't yesterday when she said she would, I'm likely retaining the attorney today. He said it would likely take 3 to 5 months to fully resolve which would fall in line with when the '25's are hitting the market.
He also told me to go pick up the truck, so I did yesterday afternoon (damn, I missed that truck). Frankly, the other engine must have been 1/2 screwed from the beginning as the truck seems to run noticeably better than it did. I had a 2010 silverado with the 6.2L and it seemed to me that it ran significantly better than this one did for the first 5600 miles; not sure that's the case now. I didn't dog it hard on the way back from the dealership which is ~45 miles away via a twisty/hilly country road, but I didn't cut it much slack*, either.
I'm still pursuing the lemon law suit, though. This has pretty much screwed my summer of pulling my boat to the Chesapeake multiple times, which is one of the main reasons I purchased the truck. And, after smoking the engine back in June while pulling the boat to the Chesapeake, along with the stories of trucks going through a 2nd, 3rd, and even 4th 6.2 that I've heard and read about , I don't believe I trust the truck to get me there and back (roughly 360 mile round trip).
* Thanks to this forum, I found that the truck has the drive modes that I was unaware of before; just didn't pay attention, I guess. Anyhoo, the Sport mode is frickin' spectacular, mainly for the added deeper exhaust noise rumbling out.