From the title I thought it was a way to emulate a Steam deck on a computer and was a bit confuse at what the use case would be.
Or just launch Steam with the command line argument that gives it the Steam Deck UI
Then again, emulating the performance may be very tough because a lot of it depends on setting the right TDP on a very specific chip. I like the recommendation to make sure it runs well on a slightly slower CPU, that should help with battery life on the actual Deck.