To be clear, this is just an alternative Linux OS. The hardware shown in the thumbnail and article is just a mockup meant to represent a potential handheld. Part of their goal is to offer equally good support for all PC game stores (epic etc) vs the “steam first” experience of the deck.
Dedicated builds for the Steam Deck and other handheld PCs are to come later this year.
Sounds locked down, and the main people involved have a crypto background. I might give this a miss.