I don't at all agree that Jude lived by Enoch's prophecies. Catholic sources can be cited for their popularly-accepted expressions about faith that are legitimate without sanctioning Catholicism whole cloth.
I'm not sure if this is your issue or not. But within my own American culture, I can quote Mark Twain to speak to Americans without sanctioning Twain's life and morality. Christians in the 1st century could legitimately quote Jewish works known to all to speak to a particular expectation without legitimizing the source in all respects.
That's what I believe was happening with Enoch. He was a well-known source of information, expressing what most people believed Enoch prophesied. Pretending to *be* the real Enoch was another thing entirely. Most likely, people knew that the work was not Enoch, that it was pseudepigraphal.
Jews decided what was Scripture in the OT era--they did not choose Enoch. NT authors did not therefore treat Enoch as Scriptures, and would therefore not be treated as canonical. They determined NT canon later, but they also accepted what the Jews had established as OT Scriptures.
If I am missing some of the process of what the Jews and Christians accepted as OT canon, I apologize. I'm ready to learn more. The point I've tried to make is that before NT Scriptures were established as canonical, they did not treat Enoch as Jewish canon.