So, my take LSY engine goes into AFM (2 cyl mode) at low rpms below 1500 rpms. Almost sounds like loose rod bearing sound.
Anyway, Try changing the drive mode. I only discovered this possible fix on the way home the other day.
Use the switch on the console. Menu from the display is different. Switch it to sport mode.
You might have to switch mode each time the car is started; like switching off AutoStop.
I’m not in the car all the time so I don’t see it often.
The REAL fix is for GM to keep AFM off below about 1500rpm