When you have laptop in a vertical stand (not that we would recommend it, gaming laptops use keyboards to cool themselves down), you can't reach the power button to turn it on. There is a workaround.
You can also create a desktop shortcut that will kick in Sleep mode:
rundll32.exe powrprof.dll,SetSuspendState 0,1,0
When you want to wake your Legion, simply interact with a USB keyboard or mouse
Sleep mode uses negligible power and is perfectly safe to use long term
— Kira