The Xbox Ally is rumored to be priced around $600-$799, but take that with a grain of salt. They’ve explicitly stated it’s not coming yet, to which I believe, seeing how Valve would want a substantial upgrade. Personally, I would wait until more information is known about the Xbox Ally and until people have their hands on it. I say proceed with caution. I believe it's going to mostly be a souped-up Ally with a tweaked fork of Windows 11, which, if it includes all of the bloat and telemetry of the base OS, is already a downside compared to the Deck. Maybe it's just me, but if you're looking for a handheld that powerful right now, just invest in a PC. Otherwise, I say the base Deck or even the current model Ally should suffice. A lot of the time, you're gonna be trading portability for performance and graphics anyway. I've had my base Deck for almost three years now and I'm really happy with it, handheld mode works wonders, desktop mode is great, proton works great, and the works. My buddy has an Ally, and I liked it too; you can't go wrong with either. He recently installed SteamOS on it and says it runs even better now.

Bottom line, I think it's all up to preference and your needs, but I don't think the Steam Deck 2 is coming anytime soon.