I don't claim to understand the details of 5 point Calvinism. However, I do understand why people would follow it. The problem we have is that we cannot possibly understand the logical duplicity of free will and predetermination. Saying that God knows everything and what everyone is going to do, and therefore knows, even before we are born, who is going to accept the salvation offered by Jesus Christ, and who isn't, while at the same time saying that we have free will to chose really doesn't make a lot of sense. It is the same logical duplicity of faith without fruit being dead faith, while at the same time works not being a prerequisite for salvation, and concerning yourself with works leading to sin, which is what your faith is trying to prevent - the separation from God. It's difficult to understand because our minds are simple. We expect simple logical true or false arguments when the reality we live in is far more complicated than that.
It's not just Christian theology that has this problem. Science has this problem too. If we follow the understanding of modern psychology free will is very much part of the core of that science. However, if we look at quantum theory and multiverse theory then the notion that we have free will is irrelevant because the state at which the electrons move is determined by quantum mechanics, so even though we may think that we have free will, the electrons that move in our brain cells and hence form certain neural pathways that we think of as decision making processes are entirely determined by set mechanical processes, and if they moved in any other way it simply wouldn't be this universe but another one because the universe itself is defined by those set mechanical processes and the pattern in which they happen.
The point is, it’s all matter of perspective. On the macroscopic scale, the one that we can understand and live in, we clearly have the free will to chose things. We can choose to go to work, we can choose to go to church and we can choose follow God or worship anything we want to. But those decisions are based on our informed knowledge and intelligence as much as anything.God’s word gives us that knowledge. It tells us simply what is right and what is wrong, but at the same time it is only by accepting the salvation that Jesus Christ gives us that we can gain that intelligence and conscience through the Holy Spirit. Simply put before you are saved you don’t really know any better than to live in sin. But then there lies itself another duplicity. If your heart is changed and you are new man in Christ do you actually gain freedom, or are your decisions now determined by the symbiosis of the holy spirit and the soul that inhabits your body? The answer is simple. In making that decision to follow Christ and accept Him you have already gained that freedom through the choice that you made to accept him. Yes, your ability to choose sin is diminished because you no longer see the value of the empty worship we have in the world for man made things and sinful ideas, but you still have that freedom because you made the choice to start with. At the end of the day you still have the choice once you are saved, even with the Holy Spirit to chose sin and be tempted by it, it just doesn't feel good anymore because you know it’s empty and worthless. How much is free will and how much is the conscience of the holy spirit within you is probably determined by your maturity in the faith, but then that would imply that you have less free will as you get older in Christ. I think maybe it simply comes down to how much you value free will and how much you value the salvation that Christ gives us. I concern myself sometimes that what remains after I die is not actually me, because once I die the sinful body that I inhabit is gone. But like a father would be motivated to care for a child even though they are not physically the same being, I must have a duty to give care for my soul, even if it isn't, what I think is the entirety of what I call myself now, because at the end of the day that soul, which is what I am at my core is either going to suffer or live in glory for eternity, and eternity is a long time! Only Jesus Christ can give my soul the ability to live in glory forever. So my choice is to follow Him.