If you want to stream games from your PC to the Steam Deck using RemotePlay, you need to follow the steps mentioned in this post.

I connected a spare keyboard I had to make typing easier, but you can use Valve’s on-screen keyboard by pressing Steam+X ... (to something like “Xbox Remote Play” or simply get rid of ...

Still, Steam's Remote Play feature allows you to stream games from your computer to your Deck in the same way that Steam Link lets you play games on your phone. But why would you ever need to ...