Wake On Lan (WOL) is successful at waking my computer from POWER OFF state but not from SLEEP

[alpumi]

After MUCH research on whether or not my Omen 15 laptop is compatible with WOL (because HP doesn't really make available much or, indeed, any clear documentation for the products you buy) I finally decided to just try out every method possible, to see if one stuck; and one did.

I was able to configure my Omen  (running Windows 10) to work with WOL, and I downloaded an app on my phone through which I could send a "wake up" packet to my computer, which works 99% of the time. (That 1%, for whatever reason, the computer just doesn't want to wake up... because, why not? So, begrudgingly, I have to turn it on manually.)

However, and as absurd as it seems to me (because afaik often computers will support WOL for "lesser" modes such as sleep and not for power on and such, not vice versa), the opposite happens when I put my computer to sleep: it doesn't work 99% of the time, and only works every so often.

I've tried everything and looked everywhere, but I can't find the reason or the solution. The only thing is that now, when in sleep mode, it won't even wake up using any input from my external devices: my wireless keyboard and mouse (connected through a Logitech USB dongle), or my Wacom tablet and two ShuttlePro multimedia controllers (all three connected through USB inputs). I'm forced to have to return from sleep mode by pushing the power button, which is a hassle, as I have my laptop mounted in closed position under my desk...

BUT, here's the clincher: if left by itself in sleep mode, it won't stay that way until I want it to wake up: at some point it'll just wake up by itself after a couple of hours. 

[alpumi]

Nice to confirm once again that help from HP is non-existent... It's official: I'm done with the brand. Never buying another HP computer; it's not worth it...