> It only works with Steam, it can't work on a desktop OS without it, despite standard layout.

This review says otherwise:

https://www.gamingonlinux.com/2026/05/the-new-steam-controll...

> Using The Steam Controller Completely Outside Of Steam

> [...] However, at least on the newly released Fedora KDE 44, the system does appear to detect it as a basic gamepad out of the box.

> [...] I installed LIMBO from GOG with GE-Proton and it worked great even with vibration.

More example games are described there as well. A few apparently get confused by the Steam Controller presenting itself as a game controller, a keyboard, and a mouse, but most seem to be fine.

Those tests were done on Linux. I wonder if it's any different on Windows.