I find it hard to understand that time-translation invariance necessarily implies conservation of energy. As I understand it, Noether's theorem says that there is an energy conservation because the laws of nature do not depend on time.
The following statement is logically true: "Because there is an energy conservation and the laws of nature do not change over time, it doesn't matter which point in time we choose, the energy content of the universe is always the same".
The statement: "Because the laws of nature do not change over time, it doesn't matter which point in time we choose, the energy content of the universe is always the same" is not necessarily true in my view.
From a philosophical perspective I can imagine a possible world where (a) time exists and (b) the laws of nature do not change over time, but there is no conservation of energy. Imagine a world where a black hole is constantly creating energy or a fundamental force that is not conservative. I do not see that energy conservation is a priori given, something that Noether's theorem implies.
Is it that Noether's theorem in relation to energy conservation is circular reasoning in some way? The theorem is based on the assumption that the laws of nature are energy conserving - when these laws don't change over time - there is an universal energy conservation. But hypothetically speaking - if the laws of nature were not energy conserving and they wouldn't change over time - there would be no universal energy conservation.