I've never seen such wide disagreement as there is in Christianity or other religions.
You're right. There have been quite a number of disagreements and conflicts among Christians. I won't deny that. If we look at World History, I've found that many if not most of the disagreements began when with Luther and the Printing Press, and I say this even knowing that there are countless skeptics out there who will instantly reach for their Bart Ehrman sources, or one of countless other skeptical/atheist authors, to strongly aver otherwise.
The truth is, Jesus didn't give us a comprehensive explanation about the world by which to live. Rather, He gave us only that which He knew we needed to know to walk with Him. Unfortunately, some people have wanted to make more out what either Jesus or the earliest Christians said than what was actually said ...................................... and some want to make much less out of it.
On the whole though, however, I don't see much disagreement among Christians about the "bare essentials."
Well, it kinda does.
I mean, if people measure the height of a tree, and they all get the same answer to within a reasonable margin of error, then it's likely that they've got the right answer, right?
I mean, if they all measure it and get a height of 20 meters, it's not likely to actually be 100 meters tall, is it?
I see your point. But how much of what we human beings engage in is as relatively simple as "measuring a tree" or looking toward the East to see when and where the Sun rises each morning?
Besides, although measurement is involved in science, that in itself isn't all that science is. In fact, the whole concept and practice of "measurement" has diverse distinctions within it that have to be recognized before we even attempt to measure even a tree, and this can one item that impedes any absolute finality about "consensus." The fact that we can recognize conceptual diversity in topics is one reason I love Philosophy and analysis; it's also a reason why we should all avoid conflation and reductionism:
But who knows? Maybe you're a physics major, and as a lowly philosopher, all I'm doing is preaching to the choir.
But do they present the things they disagree about as an objective fact?
Sometimes, scientists and theorists do "oversell" their scientific theories and scientific results and forget that science is in the business of "provisional truth." This fact is, even if its an all too brief summation, captures the basic criticism that Lee Smolin and folks like Sabine Hossenfelder have said about the way Theoretical Physics has headed in presenting its "findings."
No, I have read neither of those books. But if you'd like to buy them for me, I'll read them.
I'm sure today, many of the most salient points in these books can be read, seen or heard via the internet in other forms for free. Besides, it's not like they're the only Theoretical Physicists in town. ............... and I'm going to guess that you, like me, already have an assortment of books on physics, math and whatever else.
However, if you want me to assist in gathering free sources that you an access, I'd be glad to help.