You’ve put your finger on the crux of the matter right there, Nick. Beside this - all our Christian platitudes, important doctrines, dickering about how we or others believe, or how people handle scriptures - all of that fades into insignificance compared to this:
Can Jesus wish redemption for the brutally cruel mocker who is at the moment busy nailing him to the cross? Can He say to him, as well as He did to the suffering thief, I will rescue you from the evil that grips you right now, and I will have you with me in paradise?
In the heart of the gospel itself (Matthew 6 and also in chapter 18) Jesus taught in no uncertain terms that everything hinges on this. You need have no fear that you will be sharing Heaven with anybody you can’t forgive. Because if strife is what separates you from a brother, then either you or he (and likely neither) is in heaven. Because there is no strife in heaven.
This may be the hardest teaching in all of scripture. Believing “right things” and having all your “doctrinal ducks in a row” is child’s play in comparison - and all comes to naught in any case if you still live in the grip of unforgiveness. You may have the most excellent and well-founded reasons for truly hating somebody, Nick. And no one else can stand in that gap for you to make you do what you will not do. Thank God for free will indeed? … I guess? But nobody else is in a position to extend forgiveness to somebody in your place. If you are the wronged party, then the forgiveness has to come from you in order to mean anything to the forgiven. That is exactly why this one matter is of such over-riding importance.
Perhaps the one main help we are given to help us leap this seemingly impossible chasm is this: We are shown that there is no “us” who are the righteous and worthy ones, as opposed to “them” the cruel ones over there who are forever only fit to burn in hell. You and I and everyone else has been in that latter category, Nick. We have ourselves stood in need of forgiveness from others, who in their own turn had every good reason to think: “Never! – never will I want to be in any heaven if I’m obliged to share it with that creature!” And yet most of us as we face into that sting of repentance will pleadingly insist, but that wasn’t really me. I loath what I did to you there, and I long to make it right and show you that I really do love you and wish with every fibre of my being that I had never been the cruel jerk I was at that time. If we come to realize this and see it in each other, then previously cold hearts melt, and paradise is truly attained. But here is the tough part: Can we even make those first steps before any such repentance is even evident? Can we pray forgiveness and redemption for somebody while they are still nailing us to a cross? That is what Jesus did. It isn’t just you that struggles with this, Nick. This is all of us. Realizing that I have been that cruel person to others, and knowing that I in my own turn have need of that cleansing - that is a valuable tool to help me jump that impossible chasm and extend anticipatory forgiveness to the as-yet unrepentant. They (we) know not what they (we) do, but when they (we) are finally brought into full knowledge of it (as we all will be) - then they (we) will experience such self-loathing such as no fires of hell can match.
Your post nails this matter head-on, Nick. It is the very heart and whole of redemption, and it is exactly where God is.