I got a onexplayer for like $600 and it has the 7840u in it. No matter how you slice it, the 7840u is much more powerful than the steam deck. However, it doesn’t do well in low tdp. That’s what the steam deck is best at - low tdp gaming and battery life.
But so long as I’m near an outlet, I can play more AAA games and on much higher resolution and graphics than the steam deck for however long I’d like. On battery, only about 3-4 hours vs 6-8 hours on a steam deck.
Its about the same difference, but you can definitely tell the difference between 1600p and 720p.