Saying that Bitcoin could change the code and use less energy is simply wrong, it cannot and it would be worthless without the energy. Without the energy consumption the fair value exchange is broken and Bitcoin becomes a perpetual motion system, maybe that works for games and DeFi. For the problems Bitcoin fixes, energy is required because without it the tenets of Bitcoin (decentralized, permissionless, censorship resistant, neutral, and open) all collapse when energy is removed from the equation.