None of those sources back up your claim. They all say that Microsoft has worked with Valve to get Xbox Cloud Gaming working on the Steam Deck and that this wor

None of those sources back up your claim. They all say that Microsoft has worked with Valve to get Xbox Cloud Gaming working on the Steam Deck and that this work utilises Edge. They also imply that Edge Beta includes explicit support for the Steam Deck controls, but I was not able to verify that. If so, then that would presumably be what Valve and the MS Edge team were collaborating on.