Is It the Expansion of Space Time That Destroys Conservation of Energy?

The universe is not the same today as it was a thousand or a billion years ago. The space in which we're doing our experiments is changing as a function of time and remember to have conservation of energy You need to have symmetry in time. It changes the results of the experiments and it means energy is not conserved from one moment of space to another moment of space Right and that would also work here at the local level too, right? Like if I had a canister of gas and I expanded the space time It was in I would see energy not conserved. That's true you would create more dark energy because you've expanded space  and every new unit of space has dark