So, major caveat here: I’m a linux gamer and don’t have windows [subsystem for linux] available to test.

This actually works shockingly well for steam-steam gaming, but I’d call these steps proof-of-concept success versus “finished product”.

I’ll assume if you’re going this deep, you know how desktop mode works and you’re reasonably comfortable with the terminal. Otherwise, don’t follow random guides on the internet, and you understand that you could break things.

Obvious prerequisite: enable sudo by creating a password for the deck user

Enable installing packages via pacman: I borrowed from this guide, but didn’t follow it exactly.

# disable the deck's read-only mode
sudo steamos-readonly disable
# init the pacman keyring
sudo pacman-key --init
# populate the keyring with archlinux
sudo pacman-key --populate archlinux

Install, start, and bind the usbip service on the steamdeck (steps from the “Server” portion of archwiki linked in my original comment above)

# install usbip
sudo pacman -S usbip
# enable/start the usbip daemon
sudo systemctl enable usbip.service
sudo systemctl start usbip.service
# enable the kernel module
sudo modprobe usbip-host
# list the available usb devices
usbip list --local
# bind the Valve usb device (check the output of the above for the right bus id, mine happens to be 3-3)
sudo usbip bind --busid=3-3

Install start and attach to the steamdeck (steps from the “Client” portion of archwiki listed above)

# install usbip
sudo pacman -Sy usbip
# enable the requisite kernel module
sudo modprobe vhci-hcd
# list the remote devices (use your steam desk's ip address, this assumes you're on the same network and have addressed any firewall/configuration issues)
usbip list --remote 192.168.88.207
# attach to it
sudo usbip attach --remote 192.168.88.207 --busid=3-3

Now you can be shocked when it works instantly. Go play a game!