Your phone and tablet can be considered personal items, so you don’t need to declare those. The only thing I’d second guess is the steam deck given the statement:

Personal care goods, ornaments, and tools to be used during the period of stay by a traveler who enters the country temporarily and to be brought out again when leaving the country

But I would personally consider that a personal item since you’re not gonna be using it for commercial purposes anyway. I recommend you get a second opinion on that one.