Come to think of it, I wouldn’t really recommend any books on atheism. Atheism is not really its own thing, it’s just the result of not being persuaded by the claims of theism.
For me personally, I actually became an atheist via reading various religious texts, as well as various acclaimed spiritual novels. So sort of the opposite of what you’re asking for haha.
Recommendations based on science and humanism are okay, since that gives you a place to start looking through the secular stance on the mysteries religions claim to have all the answers for. But that also isn’t quite what you’re asking for. Many scientists and philosophers are religious themselves, after all.
Yet a third thing you aren’t asking for: I would check out Matt Dillahunty. He used to do a call-in show in Austin. Mostly just regular religious people calling in, going through their thought process on why they believed, then getting an atheist’s perspective in response. Looks like he’s still very active on youtube these days
I haven’t listened in years, and if I recall some of the most viewed clips were basically just angry arguments lol. But sitting and listening through full episodes is about as down-to-earth of atheist content as I can think of. Just addressing religious claims one at a time
I was starting to go that way in my late twenties. Started training in the gym. Thirties now, looking and feeling better than at any other point in my life. I beat my high school time for the 1 mile run by 30s recently, I couldn’t believe it.
I’ve seen people much older than you or I totally turn their lives around. I think for most people, it’s not getting older that is the problem, but rather, being sedentary over the long run is just way more destructive than we realize. Even just daily long walks makes a night and day difference