Confused and Searching, Assalamu Alaikum

Assalamu Alaikum. I'm a Muslim man and I used to engage in debates with non-Muslims - I thought I did an okay job defending Islam - but lately I'm not sure how to describe what I'm feeling. I like philosophy and history, and the mythologies of Bronze Age religions always grabbed my attention. We know those beliefs aren't true, yet I keep wondering why humans invented such elaborate stories. So many wars fought for false gods, so many sincere people and wise figures devoted to them, so many who died for those beliefs - and now I look at the modern world and see similar patterns repeating under different names. I still hold, and have held, the belief that Islam is the true way. But doubts come when I think about stories like Adam (peace be upon him), Eve, and the flood of Nuh (peace be upon him). If these events happened as told, why don't we have clear records of them? Instead we find fossils and evidence of other human species. Were Neanderthals not human? If Allah created humans as the unique intelligent beings, what about Homo neanderthalensis or Homo erectus? The archaeological evidence suggests care for the sick and possible ritual behavior - isn't that human? Where would such people stand regarding the Hereafter? One big thing kept me from turning to atheism: fear of the void, the idea that after death there is nothing at all - no awareness, no time. Lately that fear feels less convincing. I’ve thought that if there is no afterlife, then we're all headed toward the same nothingness together: coming from nothing and returning to nothing. So I'm stuck. I remain a Muslim, and I don't want to reject my faith, but the barriers I relied on are weakening. I don't know what to do next.