Paul tells us that he met in private with the leaders in Jerusalem, and then presented the gospel he had been preaching to see if he was running the race in vain.
What else could it possibly mean?
Of the multitude of times that I have read that verse over the years, I have never come away from it with the sense that you have of it.
Paul, knowing that his message to the gentiles was different from what was being taught to the circumcision by the Jewish believers in Jerusalem, went first to the 'pillars' to explain in private what he was teaching the gentiles, rather than going to the Jewish church at large which would have resulted in his voice being drowned out by the opposition, which would have resulted in his efforts being in vain.
This type of approach happens often in our own day and I have used the approach myself in presenting a proposition to a church assembly or a government assembly, to avoid being shot down prematurely.
I had much rather present my ideas to a couple of rational minded men, in private first, than to trust that my voice would not be muffled by an emotional crowd.
I believe that Paul's goal was to inform the Jerusalem Jewish believers of his message to the gentiles as in Acts 15, not in any way to get approval or sanction, but to bring peace between Jewish believers and gentile believers at that time.
Paul didn't need 'permission'. He already had it directly from the ascended Lord.
Paul was not confused. He knew very well his commission.
It was the Jerusalem church that didn't understand Paul's commission, not Paul.