You wrote:
“The problem is that you are confusing a decision with a new creation.”
Nope. I am not confusing anything here. I rarely confuse things. You are the one confusing things. Even a new creation must make a decision. If decisions did not have to be made then Christians would NEVER ever be tempted to sin Are you ever tempted to sin? Then, gee, you must not be a new creation then, right? No, of course you are, but we must still choose Christ every day.
“If we ‘make a decision for Christ’, we make a decision...but what we need is to be born again.”
Those born again are still tempted - hence DECISIONS are made. We can choose well or poorly, but we still decide. God gives us the grace we need to resist sin, but we still must choose to resist that temptation.
The rest of wha you said in no way overturned that irrefutable logic. It is also entirely scriptural. Hence, the sacred writers - and God spaking through them - repeatedly warn us to avoid sin.
A dog tends to behave like a dog. A cat tends to behave like a cat. The old man is a sinner who sometimes does a good thing. The new man awaits the redemption of the body, but is guided by the Spirit.