Cyberpunk (and Witcher 3) already runs, and honestly way better then I expected, on my steam deck. They even have a specific graphics setting to accommodate for it's obviously limited hardware, so CDPR are also aware people play their games on the steam deck as evidenced by this graphics setting.

Steamdeck is linux. Obviously this proton translation layer that is being leveraged is very capable.

For all intents and purposeses, CDPR is already where they need to be for half-decent Linux support and honestly I don't understand why they didn't already draw that last sprint that would be required to fully support this.