Given these numbers, if I was DeSantis I would just keep my powder dry, methodically prepare, and then enter at the last possible minute. He has no incentive to throw his hat in the ring at this point. By the time Iowa comes around, people will be clamoring for RDS to jump in and "save the party."
Trump is a known entity. There is not much he can (or will) do to change the public's perception of him. He is more liability than help to the GOP at this point, and everyone sees that except Trump himself.