Both sides have accidentally spilled the beans on this. AMD outed a new upcoming chip for their existing "handheld wins" (aka Steam Deck), Valve has confirmed they are already working on their next handheld, but then also said there "will be no Z2 Steam Deck" after AMD already outed their work on the next chip.
So that's Valve getting a chip AMD has already confirmed they are working on, and no other manufacturers have mentioned or have the sales numbers to get AMD interested. That's it right there.
This isn't a clear question about what you're trying to confirm here.
Are you wondering how you pull a confirmed container from a confirmed provider?
Are you concerned about supply chain attacks?