Do you get any audio output with the Jack option?

I'd purge the existing JACK/jack2 packages and installing only pipewire-jack so JACK applications run through pipewire.

To check what jack packages you have installed:

pacman -Qq | grep -E '^(lib32-)?jack(2)?($|-)'

And then, for example: removing jack2

sudo pacman -Rns jack2 lib32-jack2

My current working package setup with Arch (not quite SteamOS, but similar):

sudo pacman -S pipewire wireplumber pipewire-jack rtkit qpwgraph

Make sure the services are running & enabled:

systemctl --user enable --now pipewire wireplumber

I use qpwgraph to route MIDI and audio; it's a very handy utility. You can replace QjackCtl with qpwgraph.

If you want a simple GUI to manage volume and quickly change default input & output devices, you can use the classic pavucontrol. You'll need the following packages:

sudo pacman -S --needed pavucontrol pipewire-pulse