Please accept my apology that I am not listening to all three of these videos. I have spent many dozens of hours reading many books on this topic, watching many videos and have, indeed, published a book on this topic, so I believe I know enough about the reliability of the Bible to answer your question, however. I have two things I would like you to read. The first is my book Reasons for Belief. It goes into great detail on this topic, answering probably every question raised by these videos. It is available at www.ipibooks.com Also, here is a set of notes and power point on the question of the reliability of the Bible. Reliability and Inspiration of the Bible Reliability and Inspiration of the Bible PPT Also, Here is a link with about eight hours of audio material on the subject. https://evidenceforchristianity.org/class-series-in-san-diego-the-reliability-and-inspiration-of-the-bible/
Here is my simple answer, which is supported by a great many examples of evidence in these sources: Yes, there are a small number of significant passages in the Bible which are in doubt. But these passages make up less than 1% of the whole Bible. And besides, we have sufficient knowledge from 5000 New Testament texts and a similar number of Hebrew texts, so that we can resolve virtually all questions about the original. In the end, that tiny minority of the Bible which is truly in doubt, which is probably less than 0.2%, has no significant impact on any point of Christian belief or doctrine. I am not a huge fan of the KJV, as it was based on much less document evidence, and it is in archaic English, which is hard to understand, but our modern English translations, of which there are many, are a very reliable source of knowledge of the original inspired Word of God. You can be extremely confident of the reliability of the Bible (but it is a good idea to use more than one translation, as translations are not perfect).
One thing I can say for 100.0000 % sure is that the doctrine of the resurrection of Christ is not affected by any biblical variants. That is for sure!