It did not matter when a council "gave" the canon of the new testament to the churches, the writings of the apostles were already distributed to churches, and copies made to reach other churches, from very early on, and, they were read to those there.
The problem with that statement is that not all churches had all copies, and there were spurious epistles and spurious Gospels, and also there was material circulated that was theologically correct, some of it important Patristic material, but not of Apostolic origin, for example, 1 Clement, and many felt this should be a part of the Bible whereas others disagreed.
If you want to see what the New Testament could have been, were it not for the Athanasian, look at the the 22 original books of the Peshitta, which are the only ones found in East Syriac copies such as those used by the Assyrian Church of the East and the Chaldeans (the Syriac Orthodox and various churches that separated from them such as the Maronite Catholics gained access to the rest of the Athanasian Canon through the translation of the remaining books by St. Thomas of Harqel). A Bible with no 2 Peter, no Jude, no 2 John, no 3 John and no Apocalypse (Revelation) is interesting to consider, but I prefer the Athanasian version.
Conversely, and much worse a prospect than that, or Luther’s proposed removal of four books he incorrectly regarded as spurious (fortunately, regarding the Antilegomenna, Luther was persuaded to back down), is what we see if we look at the actual ancient manuscripts of the oldest extant bibles, such as the Codex Sinaiticus, which have some books widely regarded as spurious in addition to the 27 books of the Athanasian canon. If we had spurious epistles like 1 Barnabas or the spurious Patristic letter 2 Clement in every New Testament, that would have had a profound adverse effect.
Fortunately, while the early church did not come to a conclusion on the Old Testament (other than that it was different and at least slightly larger than the 66 book NT canon of the Masoretic text), it did regarding the New Testament, and that was our New Testament canon, which exists as a matter of Holy Tradition, which we are obliged to follow according to 2 Thessalonians 2:15 and 1 Corinthians 11:2 (1 Corinthians 11 also contains the core of the Eucharistic liturgy and the warnings of the dangers of partaking unworthily not discerning the Body and Blood of Christ our God).