The main change was that Paul began to preach the "gospel of the grace of God" to the Gentiles. And as he said, "Christ did not send me to baptize, but to preach the gospel."
Your reply there, just goes to show you don't understand the actual purpose of the Mystery preached by Paul that the gospel of the grace of God is merely an aspect of.
What changed was the direction that Israel had been headed towards - the Wrath of God, that temporarily delayed.
Why?
That God might first solve for that other fall (the one that took place in Heaven with Lucifer and those Angels who sided with him), Is. 14; Ezek. 28.
God's plan for solving for that one day is the Mystery preached by Paul, and concerns a New Creature which will one day inhabit those fallen Heavenly Places even now still the realm of the Prince of the Power of the Air and his Dark Princes, Eph. 1:19-23; 2:2; 6:12.
The gospel the grace of God being the means by which God is saving formerly lost Jews and Gentiles in this New Creature: the Body of Christ, which began with Paul, after Israel's fall and temporary setting aside, 1 Thess. 2: 15, 16; Rom. 11:25; 2 Cor. 5: 16-21; Rom. 8: 16-30; 1 Tim. 1:16, etc.
Israel is the means by which He will reclaim back the Earth that Adam forfeited the rule over, with that fall that took place in Eden, Gen. 3; Ex. 19: 5, 6; etc.
In contrast, The Body is the mens by which God will reclaim those Heavenly Places that fell when Lucifer rebelled and various Angels sided with him.
Both aspects of God's TWO-Fold Purpose: Prophecy and Mystery, of which center around the Lord of Glory, 1 Cor. 2: 8, of whom the whole family in heaven AND earth is named, Eph. 3:15.
Man are you behind on those further refinements in the understanding of God's TWO-Fold Purpose that took place after O'Hair went home to be with the Lord, but that his great contributions had made the further refining of after his home going, possible, to begin with.
Much of this was first recovered and preached about in great detail at BBS conferences, and later, at Grace School of the Bible (GSB) conferences, by Richard Jordan.
The late Keith Blades based his great book "Satan and His Plan of Evil" on Jordan's seemingly endless, dating back several decades, audio recorded teachings on all this.
Get that out of the way, Jerry, and then you'll have a clue as to why so many assert you are so off.
Two places you can order that book from, the second one has a good description of this very important, MUST HAVE book, the perfect follow up to Stam's classic, Thing's That Differ.
Resource one:
https://www.forgottentruths.com/satanandhisplanofevil.aspx
Resource two:
https://www.worldcat.org/title/sata...urvey-of-the-biblical-doctrine/oclc/302419044
Here is a nice breakdown of some of the Mystery part of God's TWO-Fold Purpose (based on Blades' book) by Nancy Paulson:
http://www.oocities.org/ambassadors4christ/writings/paulson/policy.html
2 Timothy 2:15