You said that you admit that you don't have all the answers. Neither do I.
But you also said that for the natural man to grasp the things of God is impossible....until he has a spirit.
But before the era of the spirit there were men who heard from God. Not just when men were under the law. Not just those of the Abrahamic covenant.
But God spoke to men and men responded to God. The method of responding to God that Paul explains in Rom 2 is probably the method. God left a communication device, a remnant of the image, inside us.
Men do respond to God, but do they "seek after" God? There is a difference. Balaam responded to God in all the wrong ways. The Hebrews responded to God in all the wrong ways:
Psalm 78:21-24, 29-31 Therefore the LORD heard this and was wroth; so a fire was kindled against Jacob, and anger also rose up against Israel, because they believed not in God and trusted not in His salvation, though He had commanded the clouds from above, and opened the doors of heaven, and had rained down manna upon them to eat, and had given them of the corn of heaven.I think that you are stopping too short in Romans 2 for Paul begins Romans 3 by saying "What advantage then has the Jew,..." and continues in verse 9 with "What then?" I think that Romans 2 is leading up his points and conclusions in Romans 3. Romans 3:10 is a verse which is a monumental obstacle to overcome to claim that men seek salvation apart from the prior regenerative act of God.So they ate and were well filled, for He gave them their own desire. But they were not estranged from their lust; but while their meat was yet in their mouths, the wrath of God came upon them and slew the fattest of them, and smote down the chosen men of Israel.