I don't know about that. We act on our instincts but instincts don't count as subconscious beliefs. Our instincts may lay the ground work for us to begin a chain of thought from, but a belief is something that you accept to be true. It's a mental process, not a subconscious process.
It most certainly is. While you can articulate them consciously, and even be consciously aware of some of them forming, almost all of them are formed subconsciously.
It seems true that maximizing your own wellbeing is a rational thing to do. Why wouldn't it be?
So you've gambled on the chance that something that is self-evident to you is also self-evident to your reader. Sorry, you lost. If you want me to accept this premise, you'll have to justify it.
The paradox is that an atheist can be more rational for holding a fictitious belief in God as long as it achieves their desires better than atheism does.
That's not a paradox. That's an atheist converting to theism. You entitled this thread "the paradox of atheism" which implies some sort of logical contradiction inherent in an atheistic worldview. You've failed to demonstrate one.