It would be easier for the whole world to accept the truth if all scriptures were safeguarded. You first said they were, now, you are making excuses as to why they not all are and trying to special plead the Bible.How?
The only book that needs to be safeguarded is the Gospel not the whole Bible per your standards now. And to large extent it was and its interpretation problem.
The Quran says to believe in the book revealed before it, which is the Gospels. It didn't say all the books revealed claimed to be revealed from Musa and onwards.