A man. Was Paul wrong?
First, Paul was not in the story in Acts 2. That would be Peter. But that is a small point.
Peter was not wrong. Yeshua is man.
Peter was also not wrong in his letter. 1 Peter 3:21-22 "... It saves you by the resurrection of Jesus Christ, who has gone into heaven and is at God's right hand--with angels, authorities and powers in submission to him." or again in 2 Pet 1:1 "Simon Peter, a servant and apostle of Jesus Christ, To those who through the righteousness of our God and Savior Jesus Christ have received a faith as precious as ours:" or even in Acts 2:21 and in Acts 4:12 where he calls Yeshua 'savior'. Any good Jew would know that G-d has declared that he is the only savior.