It's known Fauci created this and then released it, obviously, on purpose, then lied about it.

In theory, the way you would demonstrate that the virus didn't leak from the lab would be to show evidence supporting the natural progression, like from bat to intermediate animal to human. However, even if you did do this, it totally wouldn't satisfy someone like Tom Cotton. He would still say that even if the virus had a natural trajectory, they still haven't proven it didn't also come from the lab.