If science did discover how life started and could show it by experiment.
All that, would prove, is that life needed intelligence to make life. A creator.
Humans have duplicated many processes found in nature. That certainly doesn't mean that those processes couldn't/didn't happen without human or other intelligent influences.
The only way to prove evolution and no creator,is to have everything the same as it was in the beginning. Then not interfere with it at all.
The origin of life and the subsequent evolution of life are two separate events, although one is required before the other. But the reality of evolution is not dependent on how the origin came to be. There could have been a Godly origin of life, followed by the evolution of life.
Why do you think God couldn't create an original life capable of evolution?