The Deck's AMD Van Gogh APU can't be had in any other device and is substantially different to any other chip AMD produces.

Is it really that different? I thought it was basically Zen 2 CPU cores and RDNA 2 GPU cores. It's not an off-the-shelf SOC, but it's also not that custom. So this seems a little hyperbolic to me. I'd say it's pretty similar to the XBox Series S SOC (and Series X and PS5), which uses the same cores, just a different amount of each.

I also think it's kind of interesting that they're jumping to a VR Headset. If it's a standalone, it's probably not "low power." If it's not standalone, I think they'll have issues transferring data fast enough to be practical. So my money is on some kind of accessory, like maybe a Steam Link 2 or a controller. Those are low power, wireless, and seem to fit the bill a bit better.

Then again, maybe it is a VR headset. But I really don't see them competing at the low end on VR.