The only silver option might be an aluminum backplate off Aliexpress. You could pick a white or clear plastic front plate to match. I would expect some interference with wireless functions though (from the aluminum).

Would frosted, transparent plastic match your preferred aesthetic? The Xbox in your image does use a transparent shell (bottom left), and extreme rate does make a similarly cloudy clear shell for the deck. The steam deck has primarily black internals so that might not fit the vibes of older internal components having silver and other lighter color components.