Several extra-biblical books are cited in the Bible in addition to Enoch. I have a copy of the book of Jasher that is also cited. It is an exciting read. These are considered historical works (history books) and as such have value. It is up to each person to decide if they are inspired or not.
I personally view these works as uninspired, not infallible history books.
This link covers a number of objections similar to your own, about 4/5 of the way down.
When Dr. Thiede analyzed the fragments from Matthew’s gospel found in Egypt by what is described above as “comparative paleography,” he analyzed these fragments from the gospel of Matthew and compared them with four other well-known and reliable reference manuscripts from a commensurate and known time periods.
• Document one: 79 A.D., from the Herculaneum
• Document two: 73-74 A.D., from Masada
• Document three: 65-66 A.D., from the Egyptian town of Oxyrynchus
• Document four: 58 A.D., from Masada
The style of handwriting from the first century is substantially different from the style of handwriting, just one hundred years later. In order to date a manuscript correctly, a handwriting style that is similar to the papyrus being analyzed must be found. For this reason, the four samples above—which came from similar areas of Israel, close to the same time period, were used. The conclusions from these careful comparisons revealed that many of the letters in these very early manuscripts bore a striking similarity to the letters in the Gospel of Matthew text that Dr. Thiede analyzed.
Because many of the letters and the style of writing were so close, Dr. Thiede concluded that these three papyrus fragments must have been written between the time of the crucifixion, at about 32 A.D, and the destruction of Jerusalem by Titus in 70 A. D. This places the date of the writing for Matthew’s gospel at the time that he would have been alive and witnessed the actual events that are recorded in his gospel account.
This means that Matthew is most certainly the true author of the gospel of Matthew.
So, if the gospels are all later additions, where are all the polemics attacking such a revision of events? The documents were in existence at the same time as the proported eyewitnesses and authors. The above mentioned fragments were likely original, or 1 gen copies.
I don't think the evidence points to anything other than the gospels being reliable recordings of actual events. Here are a number of other related links.
The Historical Record of Jesus Life from Secular Sources
Historical Evidence For Jesus Resurrection
The Overwhelming Empirical Evidence for Jesus Death and Resurrection
The New Testament Passes Every Literary Test of History
Empirical Evidence for the Resurrection of Jesus Christ
Empirical Integrity of the New Testament