Valve released Windows drivers for the Steam Deck way back in March, but only now do some key features work: the speakers and headphone jack. Today, Valve added audio support to its Windows driver package for its handheld. (Previously, you had to use Bluetooth or USB Type-C speakers or headphones.)
The drivers (there are two of them), should fix these issues. You’ll also need to update Valve and AMD’s APU driver for these to work.
Just because you can install Windows on Steam Deck doesn’t mean you should. In my impressions of Windows 10 on Steam Deck, I found that the experience felt a bit rough around the edges, even with support for the GPU, Wi-Fi and Bluetooth.
I’m of the opinion the work Valve is doing on SteamOS, its Arch Linux-based operating system, is much more friendly to use with a controller. It simply feels more like a fully-baked console experience, and Valve has been squashing bugs and adding features like a lock screen and per-game performance profiles.