https://wccftech.com/steam-deck-wont-have-any-exclusive-games-valve-confirms/

As we get closer to the release date of the Steam Deck, now scheduled for February 2022 (for those who were able to pre-order a unit as part of the first wave), Valve is sharing more information on the PC handheld device and on their future plans for it.

A newly updated FAQ page dedicated to developers confirms that there won't be any exclusive games for the Steam Deck, for example. Valve doesn't believe that would make sense, as this is a PC after all and it should just play PC games.