I have no references to texts, only personal experience. I hope I can still shed some light on your question though. Only so much can be learned through teachings. We must look to personal experience to answer these types of questions. You will never know the true answer until you experience enlightenment for yourself.
I am an arahant, if I can say that. There is no perminant, separate self to be an arahant. But enlightenment occurred, and the paradigm shift occurred.
Sati is translated many ways.
If you translate it as "Mindfulness", you are talking about keeping the teachings in mind to guide your mind towards enlightenment. Once you have awoken completely, there is no need for guidance.
I think what you may be hung up on is the concept of effort. I believed I was working hard to do the "right" thing. I thought I was making choices, and pushing myself where I wanted to go.
It was just belief though. When enlightenment occurs, you see there is no such thing as effort. It stems from a belief that the permanent, separate self makes choices and acts. We do not have free will. We do not choose and we do not act.
What is choice? Choice is a thought. Take the question, "Would you like soup or salad?". You might repeat the question as a thought in your mind. Then there is a pause. Then the thought "I would like salad" comes and goes. Then a thought occurs, "I made a choice".
There was nothing between the question and answer. Did you choose the answer to the question, or did it just appear? Perhaps you have a preference? Did you choose to prefer salad over soup? With the thought "I made a choice", the belief in choosing is created. A choice always appears after it has been made in the form of a present thought.
Why do we believe we have free will? It stems from an innate understanding of what we truly are. We are the universe, creating all minds and experiences. The freedom is in the infinite possibilities of what we can experience. We have no control over our experiences. I don't choose the colors of the trees or the sounds of traffic. All experience is uncontrollable and ever changing. How could effort exist without control?
I do not have sati. There is no I to possess sati. Nothing becomes. All things are.