Thoughts from a 2018 owner to a 2021

[TrueAt1stLight]

Don't know if this works or not I don't have a 2021 (yet) to try it on....

https://gmauthority.com/blog/2021/09/heres-how-to-stop-a-gm-vehicle-from-shutting-off-engine-when-parked/

I tried this yesterday and yes, it works! You start the vehicle and keep holding the start button until the notice that auto shutoff is disabled.