We have two former athiests in our church now. You would have never known they were both former athiests though. Both have said basically the same thing. They always suspected that there was a higher power from time to time but claimed to be athiests because of some form of pain in their life that was tied to faux Christians whether it was from hypocrisy they witnessed or were told about in the news media. It wasn’t until they actually visited a church where the Christians and their love were genuine that they felt the Holy Spiit and then understood what it meant from feeling it themselves. The laws of God are written in men’s hearts. Even athiests know this but won’t admit until they understand what that means.
The whole sense of “oughtness” is a nonsense if there isn’t a God. If a God is accepted then the question arises as to what kind of God that is. Small-o orthodox Christian faith offers the classiest God known to mankind. The problems, as you say, are in the implementation of the faith. We’re sinners and find it very hard not to be full of ourselves.
Also... former atheists do tend to try to be rigorous thinkers as Christians. Their minds that were once exercised looking for clever ways to elude God with sophisms, are now getting untwisted and learning how to champion the Lord. They don’t always get it right the first time. The bible has to be understood in the right general context, or fleshly wrangles result. But if they persist looking for truth, they eventually succeed more and more in finding something self consistent.