Hi All,
YEP! Same issue here, bought my Surface Pro 7 last week and soon as its off power to battery only it randomly powers off, over and over again.
Like someone else said in this forum, if I am constantly working on the surface (when off power) it is fine, but as soon as I stop actively working on it within a short period of time (minutes) it will power off.
I have done all the Windows updates, and followed the tips to turn this and that setting off blah blah etc.
I am sure I am not the only one who has done research on this and can see that this exact issue has been plaguing the surface since 2015 - I have read all of these threads here and still no solution from Microsoft.
No help from me here I am afraid, and like some others here I wish I had have known this before buying!