Science does not prove that God does not exist - especially when theists obfuscate what they mean by god.
However you can't have it both ways. It is beyond all doubt that humans descended from non-human ancestors over millions of years. This is as certain as the fact that the earth is not flat.
Therefore there was no fall from perfection, no Adam, no original sin, and therefore no ransom in the sense that JWs believe.
You can have your own beliefs and superstitions but you cannot have your own facts.