Valve Steam Controller

Steam Deck FAQ confirms you can use it as a giant PC controller

Valve say 48 million players have used a controller on Steam

Steam Community :: Guide :: Steamコントローラー クイックスタートガイド

How To Setup Any Controller on Steam for Any Game — Tech How

Steam Community :: Guide :: How to set up an Xbox Controller

PC Games That Play Better With A Controller

All Steam Users Can Now Play Games Using a PS5 DualSense Controller

Valve's Steam Machine controller attempts to change the game - Video