You've stumbled upon one of the most profound spiritual questions there is.

Religious faith from certain perspectives is something like: choosing to believe despite being unable to comprehend with your rational mind. That's the basic core of the inquiry, you start from there and see what happens.

There's debate on the terminology, so I'll credit your first point. But there are atheists who also study theology. https://en.wikipedia.org/wiki/Hector_Avalos is one such example.