It isn’t reasonable for a few reasons. First among them is that the Bible never claims to be written by God. Yes, 2 Timothy 3:16 says that all scripture is inspired God (or possibly just that there is scripture inspired by God, translation issue I’m not competent to address), but the author of Timothy did not intend his epistles to be used as scripture. For all of the writers of the New Testament, scripture referred exclusively to either the Hebrew Scriptures or the Septuagint (Greek translation of the Hebrew texts with a few additional texts thrown in). When the Bible does refer to the Word of God, as it does in John and Revelation, it is referring to Jesus, not itself.
Second, it ignores the history of the Bible. Even if you think God should have clearly communicated his will to people in a book, the history of the Bible makes it abundantly clear that the Bible is not that book. Whether it’s the documentary hypothesis for the Torah, the politically-motivated discrepancies between the Deuternonomic History (Joshua through II Kings, Ruth excluded) and I and II Chronicles, the dubious authorship of half the Pauline epistles, or the irreconcilable difference among the four gospels, everything about the Bible’s history makes it clear that it’s an anthology, assembled haphazardly without regard to doctrinal, thematic, or historical consistency.
There’s plenty of other reasons, but what it boils down to is this: the Bible isn’t a letter from God to humanity. It’s a record of different people encountering something beyond their ability to understand, and writing it down in an attempt to understand how that experience should be harmonized with the world around them. It’s a centuries-long battle over what that experience meant and how having that experience should change the lives of those who had it. The Bible is a human book, a book written by humans for other humans. It never claims to be anything else. It has never been anything else.
Well, I believe it was a book written by humans (cause they invented it), but the Jewish belief (which Christianity is based on) is that the Torah was orally dictated to Moses by God while he was on mount Sinai.
And the Torah is full of errors and conflicting stories.
"Jewish belief" in reality is actually much more complicated. About this, and about everything, really.
Talmudic scholars have long recognized the dependencies in the Torah, as well the unavoidable issues concerning how Moses could have written about his own death. Like with almost all Talmudic debate, the solution to this problem is unsettled. This site (not a scholarly source, I know, but it works for now) goes over some of the theories put forth across the centuries by various rabbis. Their actual solutions are interesting, but not entirely relevant to this argument because, as you can see, there is no solid agreement on the solution among all Jews. There is no set “Jewish belief.” This is the nature of Judaism. The text is up for interpretation, and in fact, the creation of new interpretations are actively encouraged as a way to keep the texts alive and relevant. (I made a post on this once here)
And while certain beliefs and practices have become part of the traditional Halakhah (basically the rabbinic equivalent of dogma, but not quite the same, as the laws are decided by rabbis and are not thought to be directly inspired by God), not all Jews accept the Halakhah. Halakhah is also primarily concerned with accepted practices rather than accepted beliefs, so bringing up Halakhah when speaking about “Jewish beliefs” as we are here is almost irrelevant.
Certain Jewish beliefs cannot be compromised, the most essential being that there is One God. This belief cannot be changed, but it can still be questioned how it is possible, and how this works with certain parts of the text that possibly suggest otherwise.
"The Bible" is inherently ambiguous and self contradictory, and one cannot extract one belief from it by reading it (somehow) without interpretation. To claim the the Bible says something, and so this is what its religious adherents believe, is ignorant of the actual nature of those religions. This perspective on the Bible was popularized with Protestantism, which encouraged the individual to make interpretations of the bible outside of tradition. This is not historically how the texts have been approached, and it’s not even very descriptive of how Protestants read the text. As entanglingbriars said in another post, even Protestants interpret the Bible using reason and tradition. It is simply impossible to “believe in the Bible” without interpretation.