Journey. You can get it on PlayStation, iOS, steam (on sale for $5 atm) and epic. It is 2-3 hours short and not very challenging, but it does look absolutely stunning and has a very beautiful gameplay mechanic that you better find out for yourself. IMO it is one of the best games of all time and one that really demonstrates what the medium is capable of.
The thing works by linking an AMD graphics card with a neural processing unit via “PowerColor GUI,” resulting in rather impressive efficiency gains.
So, how does it actually work? „Linking“ is too vague to explain anything.
The only thing I can imagine is some sort of upscaling from a lower resolution, which is hardly revolutionary.
Given the problems SLI and crossfire had with more than one gpu, but in the same system, I doubt even valve would be able to combine different devices in a very meaningful way. The best I can imagine would be a pc rendering a game which is streamed to a steam deck, which in turn throws all its resources on FSR-like upscaling. Or, in case of a VR device that it handles interframe generation and reprojection locally on a stream rendered by a different device.
Of course I would like to be proven wrong.