

You can already wake the device up over LAN, USB, or Bluetooth. You could even have a separate device such as a PC or phone that sends the wake up signal to the steam deck if you wanted. I have other devices that work this way in my home already.
It’d be preferable to manage this all on device of course, but I assure you this is solvable where existing Steam Decks already reside, without needing to fix any low level firmwares.
If you want to use WOL you’ll need an adapter/dock with an Ethernet port.
Then use nmcli (network manager cli) to accept magic wake-up packets: nmcli c modify “Wired connection 1” 802-3-ethernet.wake-on-lan magic
See more info here: https://wiki.archlinux.org/title/Wake-on-LAN
Then you just send a magic packet using your Steam Decks MAC whenever you want it to wake up.
Note: if you own an OLED Steam Deck technically you can just do this over Bluetooth with a controller instead, because of the hardware update.