I have always believed that Jesus condemned Judas for betraying him:
Matthew 26:24 “…But woe to that man by whom the Son of man shall be betrayed. It were better for him, if that man had not been born.”
But, as a Catholic, I also believe the only sin God can’t forgive is against the Holy Spirit. Judas fell into despair:
Matthew 27:5 “And casting down the pieces of silver in the temple, he departed and went and hanged himself with an halter.”
Was his real sin despair? Was Jesus, knowing what Judas would do later, telling him of his despair? Or was Judas’ sin special, in that by betraying Jesus (God), Judas committed a sin against the Holy Spirit.
I don’t care for what if’s, but it applies here: What if Judas had come back to Jesus and asked forgiveness instead of hanging himself?