First: I am not a theologian but an active user of the Bible with groups for 30 years. I have one very practical comment to make to the idea that the canon of the Bible is not a very useful concept.

On the contrary, it is very useful. If you start questioning which bits of Scripture are more true than others, you start judging the Bible. The only way the Bible can build up your faith in God and correct you, is to let it judge your ideas and practice.

You may not like everything you find in the Bible, but it often turns out that the hardest bits are the bits that God uses to teach you something surprisingly good. That’s why I keep returning to this Book. It is really God’s Book, and it is no accident that the last four verses say what they say.
 Henriet