For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
JD I cannot answer your objection in the comments from where I am in China it seems to be blocked but let me just repeat what I have previously mentioned. Judas had an election, he lost it by transgression, it was given to another. He was promised a seat on the throne in the New jerusalem as one of the 12 that left all to followed Christ. Jesus lost him because he stopped abiding in Christ. It would have happened to any of them if they stopped abiding which was the purpose of warning them in the True Vine discourse.
You seem to miss the whole point of the warning that Paul made to the Gentile grafted in Christians. They needed to realize they were only connected to Christ in the Church while they remained in His goodness. As for Eli, God changed his mind as the prophet declared in 1Samuel 2. Because God foresaw the betrayal did not mean God designed it but that He used it knowing it was inevitable with Judas and the same for Saul.