I have thought of this myself. I did a study on this topic.
I read in John 18:4 that Jesus knew the plan. He knew Judas would betray him.
How did Judas “have a choice” when in John 17:12 Jesus says that none were lost except the “son of perdition,
“that the scripture may be fulfilled”. Judas was born to fulfill this plan.
If Judas “did” have a choice as some say then someone else would have taken his place, “That the scripture may be fulfilled”.
And another thing is that Judas repented.He returned the money.
He said"I have sinned in betraying innocent blood”.
As in Matthew 27:3-5 “Then Judas, who betrayed him,
seeing that he was condemned, repenting himself,
brought back the thirty pieces of silver to the chief priests and ancients”.
4.Saying: I have sinned in betraying innocent blood.
But they said: What is that to us? look thou to it.
5. And casting down the pieces of silver in the temple,
he departed: and went and hanged himself with an halter."
I often struggle with the same thing the OP is struggling with. He did repent - he tried to make it right but there was no forgiveness available for him it seems. I even get reminded of the scenes from The Passion (which is possibly problematic) where I truly feel for Judas.
You bring up a good point - it does seem like he was “slotted” for this position to betray the Son of Man. I think, however, that we must remember that it was ultimately the WILL of Judas to hand Jesus over. Also, when he repented, he repented to those who were responsible for the torture of Our Lord. From what we know from Scripture, Judas did not repent to the Christ, to God, to the one who forgives.
There are times when I, too, look into my own heart and I can see a little Judas brewing inside of me. Every sin is an offense to Christ. In no way are our sins comparable to the actual betrayal of Jesus but we must remember that it is for our sins that Jesus died on the Cross. If it weren’t for our sins, he wouldn’t have died. I think of every sin of mine as one of the many wounds to Our Lord. I would rather die than offend Christ (though I don’t always live up to this statement). I think Judas had a similar mentality - but it was just aimed the wrong direction.
He betrayed Our Lord, he realized what he did and tried to repent but decided that instead of facing Our Lord and begging for forgiveness, as we do in the confessional, Judas decided to commit the ultimate sin - losing hope. By committing suicide, he sinned and sure there is probably a chance he could have repented when the branch broke (assuming he hadn’t already died) but I think it is safe to say that he probably didn’t.
Either way - the phrase “in order that the Scripture may be fulfilled” does not, in any way, mean that Judas cannot be held responsible for his actions. His last act in life was indeed an offense against God.
It was his will and his choice.