Plutonium

As idea said, Steam decks have similar, if not the same HWID because of the same components. However, it isn't worth it to unban every single Steam deck player, because one player was enough to cheat on Steam deck and get everyone else banned. You can try and appeal the ban, and once accepted, start playing on PC. Friendly advice, because you can't really change components on Steam deck, since it's quite limited.