The Steam Deck finally has a concrete launch date, having been delayed towards the end of last year. The gaming handheld will debut on February 25 and should start shipping on February 28. However, Valve will only allow people to purchase a Steam Deck if they have reserved one; reservations will only remain valid for three days from February 25 too.
https://www.notebookcheck.net/Valve-announces-Steam-Deck-launch-review-embargo-end-and-initial-shipment-dates.596044.0.html