Source is KeplerL2, who is generally considered a reliable source for insider hardware info, particularly on AMD GPU hardware and AMD SoC for consoles.

Previously I would have personally estimated Steam Deck 2 to release mid 2026-early 2027, but the recent info about an upcoming Steam Machine made me think that maybe I should push back that estimate.

Of course even if we assume this is reliable insider info, a lot can change in couple years, so things can definitely change.