Welcome to BL, @Lostnfound. I’m glad you landed here.
Your questions are on point and very important. Several people have already responded to some of them, I hope in helpful ways. I want to respond to the most basic thought you expressed in what I quoted above: why doesn’t a non-literal interpretation of [early] Genesis put everything else up for grabs?
I’ll make two points, then fade into the background.
(1) The first thing to do is to get the meaning of Genesis right. If we confine that simply to the first of the two creation stories, not the whole of Gen 1-11, then this is the single most important article I can recommend: https://www.asa3.org/ASA/PSCF/1984/JASA9-84Hyers.html
The author (now deceased) argued that the TRUE meaning of that story is simply that everything we see (not to mention some things we don’t see) is a creation of the one, true, invisible Creator. In its original historical, literary, and cultural context, the Hebrew creation story was saying precisely that much. Full Stop. This is the most helpful article I’ve ever read on this topic, yet I hadn’t heard any of this until I read it–several months after finishing my academic doctorate. Let me emphasize that again. Here I am now, someone who’s spent nearly 40 years studying Christianity and science (in one way or another), and yet I never heard these things until after my graduate studies were completed. This just goes to show how so many Christians have never been taught how to read Genesis One properly. That’s where the problem begins: we need to educate our young adults about how to read it properly, and why that matters.
(2) We need to stress the importance of a crucial principle of biblical interpretation–namely, that God meets us where we actually are, as historically and culturally embedded, finite and ignorant creatures. To put it bluntly, God “dumbs down” his knowledge in order that we might understand and lovingly obey the good news. It wasn’t God’s purpose to instruct us about the finer details of nature in some scientifically accurate manner. This is called the principle of accommodation, and it’s been widely used since Augustine and perhaps earlier. Calvin practically baptized the notion, it was so important to him; and Galileo couldn’t have kept his faith without it. In my experience, YECs reject this idea almost entirely. For them, if the words of the Bible don’t mean exactly what the bare words signify, then God becomes a “liar.” IMO, there is no more dangerous teaching (in the realm of science and the Bible) than this particular attitude.
Many of the atheists I converse with, ironically, sound just like my YEC friends. A famous example (though I do not know him personally) is astrophysicist Sean Carroll. I remember reading somewhere that he thinks the Bible is all fables b/c God got the science wrong. I hope I have not misrepresented his view, but even if I have I do know lots of people who believe just this. Those who say this are really being sophomoric, frankly: how could God (if he exists) communicate with us in any other way? Galileo understood this full well, but my atheist friends just don’t get this. Could God possibly explain quarks to ancient Hebrews? I very much doubt it. Furthermore, in a few centuries maybe no one will believe in quarks anymore–all we really know confidently is that science will surely change dramatically over time, such that many things in textbooks today won’t be in those future textbooks, except in historical sidebars, such as where one might find (say) the idea of an ether filling all of space in a sidebar today. So, on the premise that God must tell us the true truth about nature, how would we ever be able to believe that he did? Or, if we take it as axiomatic that he must do that, then how could we ever be confident that our interpretation of those texts could possibly be true, since God must know many things about nature that no human will ever know, let alone comprehend. So, you see where I’m going here…