Contradiction with Galatians 1:2
Galatians 1:2 mentions multiple churches in a general greeting, contrasting with the singular church "at Babylon" in 1 Peter 5:13.
Galatians 1:2: And all the brethren which are with me, unto the churches of Galatia:
Contradiction with 1 Corinthians 16:19
1 Corinthians 16:19 mentions the churches in Asia sending greetings, contrasting with the focused, singular greeting in 1 Peter 5:13.
1 Corinthians 16:19: The churches of Asia salute you. Aquila and Priscilla salute you much in the Lord, with the church that is in their house.
Contradiction with Acts 15:23
Acts 15:23 describes a collective letter from apostles and elders to Gentile believers, which is a different context and style of greeting compared to 1 Peter 5:13.
Acts 15:23: And they wrote [letters] by them after this manner; The apostles and elders and brethren [send] greeting unto the brethren which are of the Gentiles in Antioch and Syria and Cilicia:
Contradiction with Romans 16:16
Romans 16:16 refers to multiple churches sending greetings, which contrasts with the singular congregation referred to in 1 Peter 5:13.
Romans 16:16: Salute one another with an holy kiss. The churches of Christ salute you.
Contradiction with 1 Thessalonians 1:1
1 Thessalonians 1:1 includes multiple authors in the greeting, differing from the singular author format in 1 Peter 5:13.
1 Thessalonians 1:1: Paul, and Silvanus, and Timotheus, unto the church of the Thessalonians [which is] in God the Father and [in] the Lord Jesus Christ: Grace [be] unto you, and peace, from God our Father, and the Lord Jesus Christ.