Many of the disciples met Christ face-to-face (and not because they were persecuting His followers).
We use the phrase “12 Apostles”; I don’t see Paul in that number.
The scripture is pretty obvious on the matter. It identifies him as an apostle. His whole story is one of someone who was radically chosen to preach the Gospel to a huge segment of the world. A large portion of the NT is written by Paul, the Apostle of Christ, who was specifically chosen, snatched from the fires of hell in a way, in a miraculous face to face encounter with Christ on the road to Damascus.
Unless you’re trying to deny some teaching that you think only exists in Paul’s writings, there is no reason to deny this fundamental aspect of history.
Nowhere does God select Matthias, but Paul is an Apostle chosen by God and given the spiritual gift as an Apostle.
Matthias was chosen by the other 11 Apostles who were too impatient to wait for God to select Paul.