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.
I'm fine with this if it means they're shooting for no-compromise 1440p 120hz with ray tracing this time around. That's the only way I'd consider a Steam Deck. Otherwise it's little more to me than just a neat novelty for people who want to get into PC gaming but can't afford to. I rather just game on my desktop.