You said:If Jesus ever does come back, he won’t be establishing Israel as a Jewish kingdom, it would be as a Christian kingdom and thus not at all what the OT prophets had in mind.
Actually since gentile Christians are accepted as sons of Abraham via the spirit of adoption, it might be accurate to describe the coming kingdom as the restored Kingdom of Israel...by which the whole world is continually blessed! And that is what the prophets most assuredly meant!
You really believe the Old Testament prophets thought the Messiah would be someone who would establish a new religion that is almost completely detached from Judaism? As long as it’s in the same place and can claim a spiritual link to Abraham? Wow. Can you show me anything in the Old Testament to support that suggestion?