You need to read, for example, the book by former atheist Antony Flew called “There is a God” in which he sets out the reasons why he became an atheist, and then the reasons why he abandoned atheism and became a theist.

It should be noted that Flew has been pretty emphatic about the point that when he “abandoned” his former atheism, he did not come within a quadrillion miles of endorsing any Supreme Being as specific as the God of Nicene Christianity that Tas Walker presumably believes in. Instead, Flew has described his post-atheistic stance as “deistic” — that is, he infers the existence of an ordering intelligence behind the universe but doesn’t ascribe any characteristics such as benevolence (or malevolence, for that matter) to this intelligence.