Windows uses a lot of power just existing, so you can’t get any of the windows handhelds down to a low power consumption. I remember when the Rig Ally first came out, the verge tested it using 5-8w of power on the steam deck, and using 16-22w of power on the Ally. Some of that is the hardware (the Deck has a really power efficient chip for low power games), but a lot of it is windows.