The newest stuff for the Steam Deck is out now, and some people have received it already. THE DECK DOCK.
With the Steam Deck Docking Station, you are able to connect your Steam Deck to your TV or monitor and play on the big screen using an external controller like the Xbox Series controller.
And yes, there were other ways before to connect your Steam Deck to big displays, but now there is an official way. The new Dock has DisplayPort, all the other things you need and an extra charging cable.
The new Steam Deck Dock will cost you around $90 in the US or €99 if you live in Europe. If this is too much for you, you may be able to find a good USB-C hub that will basically do the same thing. But maybe you’ll miss the DisplayPort connection.