I feel like once flour was invented sourdough was inevitable. Adding water to ground up grain is an obvious move as it binds it and makes it easier to work with. At some point a flour/water mix is going to be left standing and start bubbling, and when cooked it's going to get magically bigger. Boom, bread.
I enjoyed the post, always glad to see anything bread related. Baking bread has been a huge positive thing in my life, I'll never stop now (I was even without an oven for a year and learned to bake bread in a cast iron pot on a gas burner/hob). It's a rich sensory experience with all the smells and textures, and working dough is very grounding and 'real'. Every loaf is different and it's great fun waiting to see what's going to come out of the oven. I'd massively recommend getting into bread!