From what I know, most guides on piracy on steam deck involves running the game through Steam’s launcher as a “Non-Steam Game” which kinda feels sketchy to me, since the Steam Launcher portion of SteamOS is not open source, and they could be phoning home to Steam’s servers and reporting me as a pirate. Maybe they don’t go hard on pirates for now, but at any point in the future, they could pull a Nintendo move.
Sure, they could pull a Nintendo and do that; but then you’ve got a handheld running Linux. Linux that’s trying to tell the user how they should use it/how they’re not allowed to use it. And thus if they do it is guaranteed that there will be a dedicated, pissed-off Linux nerd somewhere who spends hours a day doing everything in their power to revert or circumvent whatever bullshit they pull.
In fact, if they did a “Nintendo move”, a workaround would probably be integrated into Bazzite within days or weeks.