Some Prophecy Teachers today teach that the Feast of Trumpets will be the future Jewish feast that the Church is raptured on.They also hold to the view of immanency. 2 Prophecy Teachers I know teach that the Church is not bound by the Jewish festivals meaning Christ could come on any old day.
Why would God (Jesus) have all the types and shadows of Rapture, Resurrection, and Judgment evident in a couple of Jewish feast days and then Rapture the Church any old day?
The most direct answer to your question is that the timing of the Rapture is a secret. Therefore it can’t be connected to any other specific event of the End Times, whether Jewish or Gentile.
Personally I think it’s a number specific event rather than a date specific one. What I mean by that is according to Romans 11:25 there seems to be a predetermined number of believers for the Church and when that number is reached the age of the Church is over. The Greek word translated fullness, or full number, comes from a nautical term meaning the size of crew necessary for a ship to sail. Before it was reached the ship couldn’t sail, and any extra was surplus. The one translated “come in” means to arrive at a destination. So by his choice of words, I believe Paul was talking about the Rapture.
No one knows what that number is, or how close we are to reaching it, but theoretically the very next person who gives his or her heart to the Lord could complete the church’s membership. If so, the rapture would occur. Therefore, it could happen any day.
All of the Seven Levitical Feasts are thought to have both a historical and a prophetic fulfillment. Passover, Unleavened Bread and First Fruits were all fulfilled in the Lord’s 1st coming. I believe The Feast of Trumpets will be fulfilled by the 2nd Coming, Tabernacles by the Millennium, and Yom Kippur by the Great White Throne judgment.
That leaves Pentecost. Some believe it was fulfilled in the birth of the Church, and some see and End Times fulfillment yet to come. (If the Rapture does take place on a Jewish Feast day, Pentecost is a much more likely candidate than Trumpets.) But to tie the Rapture to any known event is to destroy the Doctrine of Imminence, something many in the Church hold dear to their hearts.