The Switch does do stuff on sleep, so maybe it isn't the best example. Older Nintendo handhelds were bizarrely resilient, though.

Still, I've never pulled the deck from being left on sleep in its case and found it charged. Which makes sense, it's a x86 PC. All I'm saying is its sleep mode is somewhat more reliable than most Windows x86 devices, but it's not on par with ARM devices meant for mobile use from the ground up. You can only do so much at the OS level.