“errors and contradictions from the writings of the real Apostles”
my friend, how do you know that the Apostle John wrote the Gospel of John.
there is only one way to know for sure, i suspect no non-Catholic will be brave and honest enough to admit it.
It didn’t take the RCC to come up with that when any other scholar could and did conclude the same thing.
1. He was evidently a contemporary of the events described:
The writer was personally known to the High Priest and entered his residence along with Jesus on the night when Jesus was arrested (18:15). This author alone mentions the fact that it was the servant of the High Priest who had his ear cut off by Peter (18:10). This author deals with questions which are relevant to the period prior to AD 70 and not with controversies which were occurring in the second century connected with the Gnostic and Ebionite groups. (cf 6:15; 11:47-50) Many other details indicate contempoaneity with the events described.
2. He was Jew of Palestine:
The opening words of the book demonstrate an acquaintance with Hebrew (cf Genesis 1:1). On three occasions there are quotes from the Hebrew (12:40; 13:18; 19:37). There is intimate knowledge displayed regarding the Hebrew festivals viz. the Festival of Booths (7:2 Tabernacles KJV) the Feast of Dedication (10:22) and the Passover (21:13,23; 6:4; 13:1;18:28). Jewish customs and ways of thinking are familiar to the author eg. questions about purification (3:25;11:55), marriage customs, especially the method of arranging the waterpots (2:1-10); customs relating to burial (11:38,44; 19:31,40). Knowledge of the geography of Palestine is demonstrated such as the descent from Cana to the Sea of Galilee (2:12) and also the fact that Jacob's well is deep (4:11). Specific places such as Ephraim (11:54), Mount Gerizim (4:20), Jerusalem and the Kidron valley (18:1), Bethsaida and Siloam (5:2; 9:7), and Golgotha (19:17 etc).
3. He was John, the beloved disciple.
This can be deduced in a general sense from the above facts. He indicates the precise hours when particular events took place (1:39; 4:6,52; 19:14). He records quotations of the disciple Philip (6:7; 14:8), Thomas (11:16;14:5), Judas (14:22), and Andrew (6:8-9). He leaned on the breast of Jesus at supper on the night of the betrayal (13:23-25) and was among the three 'inner circle' of Peter, James, and John. Peter is distinguished from this author by name in 1:41-42;13:6,8 and James had become a martyr very early, long before the Gospel was written (Acts 12:2). He has a particular way of introducing himself (John 13:23; 19;26; 20:2; 21:7,20). These facts cumulatively make it difficult to come to any other conclusion, but that John was the author of the Gospel which bears his name.
Source: The New Unger's Bible Dictionary, Merril F. Unger, Moody, Chicago. 1988. p 701.