It is an apparent "lie" that Paul wrote "Romans". “I, Tertius, who wrote down this letter, greet you in the Lord” (Romans 16:22 )
Everything that Paul is said to have written is not a lie. Apparently he said that I am the foremost "sinner" of all (1 Timothy 1:15), which although a possible exaggeration, is somewhat on point. A better translation might have helped, in that he would be the leading sinner, as in that he is the foremost leading sinner, in that he leads the "most" sinners (Matthew 7:13-15). It is the dragon/devil/Satan who is the father of lies. Paul is just one of his sons, as are those who follow in his path (1 John 3:8). Paul's followers would not generally be listed as "liars", but as the "deceived" (Revelation 13:14) by way of the beast with two horns like a lamb, the Roman emperor Constantine, in which Paul was just one of the two horns like a lamb/Christlike. Peter would be another one of the "horns like a lamb". Peter was not a liar, per se, but just a "worthless shepherd" (Zechariah 11:17). Paul said he acted fraudulently to save the Jews (1 Corinthians 9:20). Is that lying, let the reader determine for themselves. That same deception occurred in 2 Corinthians 12:16, in which he acknowledges his deceit. Proverbs 12:17 " An honest witness tells the truth, but a false witness tells lies." (Matthew 23:15) and entangle the naive. In fairness to Paul, he was following the prophecy of Zechariah 11:7-10, whereas he was just being the shepherd/leader of the "flock doomed for slaughter", just as Judas was forecast as the "shepherd" to follow the money (Zechariah 11:12-13). The tare seed, gospel of lawlessness/grace, was of the devil (Matthew 13:39-41), and Paul was simply his messenger. Both wind up in the lake of fire (Revelation 20:10).