

Not an RPG, but in the Thief series the hardest difficulty usually means that you aren’t allowed to kill anyone. Many people even try to play the games as a ghost. Meaning the only sign of their presence after leaving is the stuff they stole. Every door has to be closed and locked again. Keys stolen from guards have to be returned (in lieu of a game mechanic for this you have to lay it on the ground behind them).
People do challenge runs of the Gothic games as pacifists. So it isn’t part of the games but doable with some shenanigans.
Don’t know if it’s possible with SteamOS. But in KDE you can select different power profiles for battery powered and on a power supply. And those profiles can be configured.