Matt 24:39-41 And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be. Then shall two be in the field; the one shall be taken, and the other left. Two women shall be grinding at the mill; the one shall be taken, and the other left.It appears that there will be a separation when Christ returns. Like in the days of Noah, some will be taken away to judgment and those left behind will enter the millennial kingdom without dying. This is the preservation of the flesh Matthew 24:22. I think Schofield got it right, this is not the rapture, this is the second coming when Christ will rule with rod of iron.
I separate it into two ~3.5 year periods. The first is the tribulation. This is followed by the rapture in chapter 7 of revelation, followed by the wrath of God.
But it’s just my opinion. I used to “know”. I’ve been humbled on this one.