These days on non work hardware, about the only time I use windows is to play one particular game, that while it will work in Linux can be fragile each time it gets updated...
For quite some time I was putting up with the laptop just completely ignoring all of the sleep settings and locking the screen after 3-4 minutes. This can be annoying if I decide to enjoy a cuppa while space engineers is refining some plutonium, but aside anything else this is a really basic thing for an operating system. I assumed this must be some obscure corner case, heck I've used tools to batter windows into behaving how I want, rather that how Microsoft think I should use my hardware...
Judging by the number of support forum posts, its a way more common issue than it should be, compounded by the fact most of the "solutions" were trivially obvious and incorrect.
The one thing that finally fixed it for me was the registry key
Computer\HKEY_CURRENT_USER\Control Panel\Desktop\DelayLockInterval
which for me was set to a value of 0xffffffff, I set this to 0 and finally the machine doesn't lock if left alone.
Of course when left alone the screen randomly dims and brightens every few minutes, frankly well... life is too short - I'll live with it given the random adherence to system settings - all said and done my actual OS for the laptop works properly.
The fact that power settings (for some) behave so poorly, for such a basic functionality, is flabbergasting, I wonder if this level of quality is reflected in more complex parts of windows under the hood...