Well, first I want to be clear what I mean when I say I am an atheist.

Definitions from Oxford Languages via Google.

atheist - a person who disbelieves or lacks belief in the existence of God or gods

agnostic - a person who believes that nothing is known or can be known of the existence or nature of God or of anything beyond material phenomena; a person who claims neither faith nor disbelief in God

As an atheist I simply see no evidence of God or gods. Unlike an agnostic, I do believe we can know the existence or nature of God by there being evidence of such. Show me real proof and I mean a miracle that can't be explained by nature and I will believe. "God does not heal amputees."

First, we need to get life started. This is the term for that.

abiogenesis - the original evolution of life or living organisms from inorganic or inanimate substances. "to construct any convincing theory of abiogenesis, we must take into account the condition of the Earth about 4 billion years ago"

We don't know precisely how life began, but it could have been from lightening strikes. https://www.newscientist.com/article/dn14966-volcanic-lightning-may-have-sparked-life-on-earth/

Now on to the topics of evolution and natural selection and the development of more complex life.

evolution - 1. the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth. 2. the gradual development of something, especially from a simple to a more complex form. "the forms of written languages undergo constant evolution"

These definitions leave out the most important part which is natural selection.

natural selection - the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution

Natural selection is the "engine" that drives evolution. It isn't random at all and we've had BILLIONS of years to get to where we are today. Organisms that are best suited to their environment SURVIVE and reproduce. Add in some naturally-occurring mutations and you have everything you need for diversity of organisms and the growing complexity of organisms. (badly mutated organisms die off, organisms with beneficial mutations survive and reproduce) Evolution is a theory in the same way that gravity is a theory. We have mountains of evidence of evolution, the same way that we have mountains of evidence of gravity.

Here are some videos.

Richard Dawkins demonstrates the evolution of the eye

https://www.youtube.com/watch?v=Nwew5gHoh3E

Richard Dawkins demonstrates laryngeal nerve of the giraffe

https://www.youtube.com/watch?v=cO1a1Ek-HD0

(basically shows the length and path of this nerve is a bad design, but can be explained by evolution)

I don't subscribe to "religion". Many times it is just people claiming to do one thing while doing another. I don't care what you claim you believe. I care how you act. My daughter, who happens to be a Christian, was once asked by a friend why she wasn't bad. She explained that it was just easier being good. People instinctively know this. Even animals know this. We don't need a higher-power to tell us.

Now, my issue was the Bible. Why would such a document exist in the first place if Jesus Christ wasn't a real person. I think I found the answer.

https://solarmythology.com/ (not my website, but my username is based on this notion)

Read the introduction to get a basic understanding. I believe there is a lot more too it than just solar mythology.