Scripture does not say that you are in the process of dying to your old nature. It says it has already happened. "Our old self was crucified with Him" (Romans 6:6). That is not a goal to pursue. That is a reality to believe. Over and over again, the New Testament speaks in terms of completion. You are dead to sin, not dying to it. And if that's true, then the entire framework of internal conflict begins to fall apart.
Because if you believe that your old nature is still alive, then every time you fail, you will assume that that failure is proof of who you really are. You will interpret your wrong behaviour as identity. And that will keep you trapped in a cycle of guilt and shame, where you are constantly trying to fix something that God says is already gone.