Yeah I don’t think the sandbox version works in the demo. But sandbox isn’t Minecraft creative, more like survival Minecraft. Also I think I misremembered, it might be called Freeplay and not sandbox, my bad.
But yeah, there is easily +100 hours, in the vanilla game. Not sure if mods works on the steam deck, but mods adds 1000 hours of ekstra gameplay! One of my favorite memories, is playing a death world with a friend. Its normal Freeplay, with biters turned up , so they’re more aggressive. That’s something you should try when you get comfortable with the base game, and if you like playing with biters!