I recently purchased a ROG Flow X16 (GV601RM). I setup it up and tested it out and everything appeared to be well. I then added a second SSD and upgraded the RAM. Memory tests passed and games all worked great. I shut it down for the night and left it plugged in overnight. The next morning it wouldn't power on. Searching support, I found how to force a CMOS reset, which allowed the machine to boot again, but when booting the power button LED wouldn't light up, the touchpad didn't work, and once windows loaded the screen would shut off and the keyboard backlight would shut off. I switched the RAM back to the original DIMMs and the system booted normally again, until I left it off overnight again.
After trying dozens of different things, I found that removing the 2nd SSD resolved the issue that after a CMOS reset that the touchpad/screen etc. wouldn't work. I also found that if I power down the laptop, close the lid, unplug it, then move it around like it was in my backpack it will not power on until I do a CMOS reset.
So where I'm at is I have an annoying workaround to deal with what feels like a faulty bag detection logic or set of sensors.