Only the 144,000 are sealed.
There is no scripture of God sheltering saints from the GT plagues.
Plus, it would be horrifying to us to witness the destruction of our neighbors and we just have to stand there and cannot help.
It is anti faith/hope to tell new believers to expect all this.(Also, God has not told us to be preppers in His word).
We are saved by hope and should pray to be counted worthy to escape these things.
The beginning of the GT is when the partial blindness of national Israel is lifted, and also the fullness of the Gentiles is complete, meaning no more Gentiles will be newly saved. Now the focus goes back to national Israel and all Israel shall be saved and become part of the Church, the Bride of Christ. Jesus is not a polygamist. There are not two brides, so who do you think are they that "come out of the Great Tribulation, if the Bride has already been raptured? Do you think God favors the wild olive tree over the natural?
As you can see by the letters to the seven churches, the last four are known denominations that go to the second coming beginning with Thyatira, the Roman Catholic Church and Orthodox Church, the only denominations who revere Jezebel, the goddess and her godchild Babylonian mystery religion who revere the goddess even more than the child. (Then Sardis, the Protestant denominations linked to the Reformation, from Lutheran, Reformed and then Methodists in white robes at the end of that era; then Philadelphia, who take holiness and keeping the Word of God to a new level; then the falling away of the heart nominal Christian we have now of Laodecia.)
Many of today's Christians have to overcome as they are in name only, but not born again. They have to be tested by tribulation. It is they that will be beheaded if they do not take the mark of the beast, but survive the seals. Those who have already overcome before the start of the GT will be protected, and not have to be tested by martyrdom. The Philadelphians are the Christians who will be "alive and remain" to the second coming, as all other types of Christians who are neither hot nor cold, but are nominal Christians will be martyred.
During the first half of the GT, the martyred will be nominal Christians from before the start of the GT. The second half, will include Jews.
Revelation 12:
13 Now when the dragon saw that he had been cast to the earth, he persecuted the woman (Israel) who gave birth to the male
Child. 14 But the woman was given two wings of a great eagle, that she might fly into the wilderness to her place, where she is
nourished for a time and times and half a time (the partial blindness is healed), from the presence of the serpent. (3 1/2 years) 15 So the serpent spewed water out of his mouth like a flood after the woman (national Israel), that he might cause her to be carried away by the flood. 16 But the earth helped the woman, and the earth opened its mouth and swallowed up the flood which the dragon had spewed out of his mouth. (National Israel coming into the Church was protected.) 17 And the dragon was enraged with the woman, and he went to make war with the rest of her offspring (the Church), who keep the commandments of God and have the testimony of Jesus Christ.
Revelation 13:
5 And he was given a mouth speaking great things and blasphemies, and he was given authority to continue for forty-two months (the last half of the GT, another 3 1/2 years). 6 Then he opened his mouth in blasphemy against God, to blaspheme His name, His tabernacle, and those who dwell in heaven. 7 It was granted to him to make war with the saints and to overcome them (more martyrs of both Jew and Gentile). (Again, remember the Philadelphians will be alive and remain protected during those 7 years of GT.)