I've been having the exact same problem. These are not BSOD, and Windows doesn't generate an error report, it simply turns off and back on again. As some others have suggested this appears to happen when using the laptop after it's been asleep--I have never experienced the issue when using the laptop after a full shutdown/boot cycle.
In another thread I read that the issue might have to do with corrupted Windows image during manufacturing, and that reinstalling might fix the problem. I'm trying that now.
Did you resolve your problem with reboots? In this post you mentioned you would do a windows re-install. Did that help?
I have a new ryzen 5, 16g unit that does the same thing and Im deciding if I should return this for something else. I really like the form factor but I can't live with this issue. Is your device a ryzen 5 or 7?