The Steam Machine might have turned out to be a disappointment (mostly down to its price), but the Steam Controller remains a very useful thing.
Should you be the tinkering sort, the OpenPuck project doubles down on the Steam Controller’s Swiss Army Knife-like tendencies, allowing it to emulate Xbox, Nintendo Switch, and PlayStation controllers.
The OpenPuck is the work of Github user safijari, and the project is based around a Pro Micro NRF52840 board. This $8 device can be flashed to emulate the Steam Controller’s regular wireless puck, and translates the controller inputs to their console equivalents while also enabling Steam-specific features (via Hackaday).
Although safijari says “the Switch and PS3 modes have been verified to work on real consoles,” so your mileage may vary. By the looks of the project’s page on Github, DualSense emulation is currently supported for PC only, and there are various caveats for emulation support to consider for each potential mode.