Everyone is trying to make a “Steam Deck killer” but none of these companies understand what makes the Steam Deck so good. Its not the touchpads, the back peddles, the good motion controlls, the capacitive sticks, or the good grips (although they help), its the software that truly makes a steam deck different from every other PC handheld. Everything just works and everything works together. Fundamentally you cannot recreate that experience with another poorly designed launcher, you need a true controller UI.
As of now no 3rd party handhelds ship SteamOS by default