I understand your dilemma! But would there still be a dilemma for you if you could answer the questions I posed? What OT prophecies are there that Messiah, at His coming did not or is not fulfilling from the cross to the end of time? According to my understanding of OT prophecy the only thing that will be fulfilled when Christ comes a second time is the bodily resurrection to everlasting life or everlasting death, the wrath of God being poured upon the world of the ungodly, the Judgment of "the dead"; that is the second death for those who have no part in the first resurrection, and the creation of a new heaven and earth where believers will dwell with Christ (not for 1000 years) FOREVER! Messiah fulfills all prophecy at His coming! This is not at His coming again, but at His coming! This is what all the OT prophets looked for and spoke of. There are no OT prophecies that speak of Christ establishing a literal kingdom upon earth while time still exists. The only kingdom on earth in time is the militant church! The triumphant Church will not come to this earth, but to the new earth when it comes down from God out of heaven as the holy city, new Jerusalem, prepared as a bride adorned for her husband!
When Christ comes again there will not be another 1000 years of time. Time will be no more because eternity begins when He comes again in glory. That is when His Spiritual Kingdom will be complete, and then will be a literal or physical Kingdom on the new re-created earth.
The 1000 years represents TIME! But God dwells outside of time in eternity. That is why we read to God a thousand years is like a day and a day like a thousand years. And also that a thousand years in the sight of God are but as yesterday when it is past, and as a watch in the night. Time was made for man, but when Christ comes again time will be no more! You cannot have time no more, and another 1000 years of time! Time exists in this age, but in the age to come is eternity.