Steam Controller requires third-party software for Xbox app and PC Game Pass compatibility

Games launched via the Xbox app can't communicate with Valve's new Steam Controller, unless you download fan-made input translation apps from GitHub.
eTeknix

Steam Controller Does Not Work Properly With Xbox Game Pass as Players Find Their Own Fixes

Valve’s new Steam Controller was created to offer a more integrated experience with Steam on PC, but people hoping to use it without problems on Xbox Game Pass are facing an important limitation. As ...