Debating an atheist is an act of vanity. You are not really debating them, you are trying to comfort yourself over the nasty, biting doubts you harbor against the whole idea of God and heaven. Atheists will not be won over by reason, because the gospel is not reasonable according to human understanding. Human understanding tells us to acquire, grow, procreate, and feel as much as we can before we die. The gospel tells us to forsake the flesh for that which is not visible to our eyes. Faith is, by every human definition, an unreasonable and even silly thing to consider until you come to terms with the fact that all things are vanity. Death and entropy are the only real and permanent things, if God be a lie, in which case do whatever you desire, for tomorrow we die.
I am going to suggest something shocking. Every living thing which crawls upon the earth knows that God exists, right down at the root of their very consciousness, from the lowliest bottom-feeding prawn to the modern-day Albert Einsteins among us. But, all living things have the ability to ignore what they know within themselves, if knowing it competes against our fleshly desires. We all have the ability to make the nose on our face vanish from our eyes. If you don't believe me, close one eye and look into the inner corner. There it is, big as life, for both eyes singly. But with both eyes open it just disappears. Humans have the ability to do the same with everything and anything in their lives. If you know a narcissist, they prove that with their every word and action.
Atheists know God exists, right down in their spiritual guts, beyond the reach of their meager intellect's ability to dismiss. Debating them is pointless. The rat will run the maze following the exact same path it knows will lead to the cheese. All you can do is shine the light of Christ and be patient, praying and waiting for God to move in them. Prayer is the only device which might reach them. Words they will not hear.