Sorry for the late reply. I've been putting off answering some things on here.
I find it surprising that you would question the reliability of the Tanach. Aren't you Christian?
In any case, I think the Tanach is reliable, but the meaning of that reliability is fluid and is bound to change from person to person. I personally would say that first and foremost, I believe in Tanach out of faith in my religion, which includes an unbroken tradition in the validity of the Tanach. Secondly, as time moves on, more and more archeological discoveries are being found that further validate the Tanach. Not everything has been found yet, but I think we're slowly but soundly heading in a positive direction. Thirdly, some of the Tanachic prophecies have already been fulfilled.
Here's why I think the meaning of that reliability is fluid. In my opinion, Jesus didn't fulfill any Tanachic prophecies. A Christian, on the other hand, would say that he did, in fact, fulfill many, and that's a basis for belief in the truth of the prophecies of the Tanach. A minimalist person in Biblical archeological terms would claim that multiple archeological discoveries actually show that the Tanach is entirely or almost entirely unreliable. Such a person could still be religious. For example, Werner Keller, who wrote The Bible As History, was a Christian pastor but was clearly minimalistic in his views. Some random examples: He thought that David wasn't the name of King David but was a later misinterpretation of an ancient Mesopotamian tribal leadership title, the "davidum", and he thought that Manna wasn't literally miracle foodstuff from heaven but a kind of sweet plant. So Keller's and other religious minimalists' views on the Tanach would be that it's either much more symbolical than viewed by most or that we simply don't have enough understanding of the Biblical lingo to correctly interpret that when they say X, they actually mean Y.