Sorry but I didn't read very much of the thread but here is my experience.
2024 Sierra Denali, 37K miles, no noise or any other indications, I was going to have the inspection on my next oil change
I stopped at a stop sign, waited my turn and when I pressed on the gas it died. Tried to restart and it would not. Waited a few minutes and tried again. It started and said low oil pressure so I limped it to the nearest safe location and parked. Called Onstar and they sent a tow truck. He says lets try to start it. We do and no check engine light. Seems to idle fine and although I'm in a noisy location, it sounds okay. He said he had the same situation with a Tahoe a few days ago. The dealership I use is only about 5 miles away so I decide to drive there. Then halfway there while I am driving 65mph on the interstate it completely shuts down. I was in the right lane and pulled off to the shoulder. Kinda scary. Call Onstar again and a tow truck comes and takes it to the dealership. This is on a Saturday around 5:30pm by the time it gets to the dealership. They call me on Monday and tell me it needs an engine replacement but they don't have one in stock but have one coming in soon. They following Monday they call and tell me it is ready. They had it less than 6 working days. So far, so good, 5 days and about 200 miles.
Side note...I looked at the paperwork and it showed $17,516!!!