If you are going to use those words of Paul to determine what is important, then knowledge of the birth and life of Jesus Christ, not to mention His resurrection from the dead according to what the prophets told earlier, is also not to be taught.
His miracles and all the proofs of who He was are verboten.
That 'baptism is not the first thing one presents to unbelievers' is all Paul is saying, and that knowledge of Christ taking our sins on Himself and His resurrection from the dead, (the gospel}, were to be preached first.
One step at a time.
Paul said Jesus did not send him to baptize but to preach salvation.
1 Corinthians 1:17
For Christ sent me not to baptize, but to preach the gospel: not with wisdom of words, lest the cross of Christ should be made of none effect.