Paul makes it clear in Romans chapters 9-11 the Jews were cast off. Those Jews in Acts 2 to whom Peter preached the first recorded gospel sermon were lost, NOT OF GOD. Yet those few Jews (”remnant” as Paul calls them in Rom 11) that believed, repented and were baptized became Christians, God’s chosen and had their sins remitted (saved). All the rest of those Jews remained lost for they rejected Christ and His NT gospel in unbelief.
The OT promises made to fleshly Israel have been fulfilled.
The idea fleshly Israel is still God’s chosen comes from the non-Biblical, man made idea of Premillennialism.
There is good reason to believe the ones Peter preached to were of the Essene/Zadok priesthood variety Jews. Your faulty reasoning presents God as changing His mind, as if He cannot see the end from the beginning. Your arguments also sounds like a Catholic assertion or Lutheran. Have you ever stopped to consider the pre incarnation rituals the Jews practiced from time of Moses, which show that belief in Messiah is what God accepts for His Grace to be activated?
Really. please explain to me when the Jews possessed all the earthly territory God promised? All Gods promises to the Jews are NOT fulfilled yet. But they will be. To the last dot. God is not a liar