About two weeks ago, I went out in the morning to start my vehicle (2022 Yukon Denali; 6.2L) and the electronics were having a seizure. All of the warning lights were on; had a "service infotainment" message; and it was cycling "[collision alert/cameras/parking assist/etc.] disabled." Then, it wouldn't turn over when I tried to start the engine. On the second attempt, the entire system shut down and the battery was completely dead. The vehicle wouldn't even receive the lock/unlock from my clicker.
I used the GMC App and called for roadside to jump the battery and about 25 minutes later the vehicle was running again and none of the above errors, etc. were present. Everything is back to normal (save for autostop, which is actually nice because I don't have to disengage it every time I start it up anymore). My guess, because I never took it to the dealership, is that there was just a software glitch that caused something (e.g., radio, etc.) to stay on overnight and/or something else related to the technology guts of the vehicle, which was essentially "reset" when the battery died. Seems like something similar happened to you, but it just reset because the vehicle was off for an extended period of time (overnight). I'm not sure the vehicle really "turns off" when you quickly turn it off and on.
All the tech is great, but when it doesn't work, and the whole vehicle is built on that foundation, it is very annoying. GMC is definitely still firmly in the "car manufacturer" category, compared to the likes of like a Tesla, who I would consider a "technology company that makes simple cars." Hopefully, GMC can begin to dedicate more resources to the technology side of its business as that is the way things are going. From what I have seen so far, I don't think I could really trust SuperCruise, or whatever they are calling their FSD on the Sierra/Escalades.