Exactly, reading what others have written through the ages.
You said, “My gosh, yes I would think that’s something that goes through every growing intelligent child’s mind. And we resolve it and get on with living in the real world, while philosophers get to be kids all their lives.” But it is The existential question that all civilizations that have written anything have asked, and tried to answer. What do all religions have in common? An origin story.
Whether it’s “out of chaos” or “sprung from the soil” or a “cycle”, all the old stories explain a beginning. Some called themselves, what we now translate into, “the human beings”, but then they met other beings just like them and had to reconcile their origins with the others. When a few became many, and empires became aware that previous empires had fallen, they tried to claim their story encompassed the others, that they would be the unifying force and bring harmony to the rest. But they’ve all failed.
In the book “Ishmael” https://www.cliffsnotes.com/literature/i/ishmael/character-list-and-analysis/ishmael, a psychic ape gets a man to tell the story of the origin of humans, so he starts with the big bang, then the earth, then evolution, then us. The ape points out that his story puts humans at the center of the story and as the pinnacle, just like every other myth.
Sorry, CC, maybe it’s the Oxycodon prescription I’m on, but I don’t think your views on where humans fit in the grand picture are something that unique. I agree with them and your expression of them is well worth the effort, and they are unique in human history, but many people have been working through these ideas, since at least 1859. Geology became a science in 1785. Not being the center of the universe was kind of a big deal before that. These discoveries have all affected the human psyche.